General Royal Python care

Hello, I am new to this forum and am looking for assistance for my viv for my first pet, a ball python. Firstly I bought a large viv from pets at home, they told me it would be okay and i later discovered that the medium viv may have been enough, my python is 18 months old and I could guess near 4 foot. The heatmap they supplied me was struggling to heat up such a large viv and for the first day I struggled to average an air temperature of around 24c.
Today I bought a basking lamp to try counter this (something I wasn't expecting to need to do an have no knowledge on) the guy sold me a 60W bulb and a ceramic dish wish is mounted atop the viv and protected by a cage and is doing a much better job of heating the tank up when paired with the heatmap. I now have an air temp in the tank of around 28c. However I am now curious if the heatmap is necessary, I later found out its not recomendded for pythons due to the risk of thermal blocking. I am paranoid however the cold end of the viv may plumit to low, or even the lamp may struggle to heat up the entire viv without it, the snake still spends most of its time ontop of the heatmap in the shelter, which was initially meant to be the hot side, but because the light fitting is on the other side has now become the cold side but is still evidently fairly warm at around 25c. what is the best way to get an overall warmth in the tank? will a 60W bulb be enoug to heat that tank as a hole? on the platform its about 31c directly under the light. Is that too high? could that harm the snake? I am hoping to remove the heatmap completely if possible, but then comes the problem of maintaing heat in the night, I am able to keep the light on but I also read how this can cause stress for the snake, so i am confused as to how I would maintain any kind of heat if the lamp is off in the night and the heatmap has been removed?
Any tips/products/procedures are appreciated.

How is your humidity with the heat lamp? Lamps have a tendency to dry out your air.
How is your heat mat controlled? You should have a thermostat to adjust your temps so that it will not burn your snake. Heat mats also do nothing for ambient temps.
A larger enclosure is not a bad thing but not always necessary. Also you should have a day/night cycle as your snake can get stressed from constant light, remember they live in dark termite mounds

Thanks for the reply, I recently discovered that the viv I was sold was meant for a beardie, so i'm debating taking the shelves out (leaving me room to put a shelter directly under the lamp in the hotter end) . I'm presuming to eliminate use of the heat mat at night as my house will not maintain the tank as a suitable temperature I will need some sort of night light to run to keep it at the night temperature? The viv in the link is the one I was sold. https://www.google.co.uk/search?q=ex...M4YkiLi0xMM%3A
Thanks again for your help.

ADDED - Also my heatmap is controlled via thermostat. the package supplied to me with the viv came with one heatmat that is controlled via thermostat and a separate thermostat to measure air temperature which is currently reading 28c with the light on (The probe for air temperature is near the heat lamp)

As long as your cold side temps don't drop below mid 70s ( 24-26c ) I would simply use the heat mat to maintain a hot spot throughout the night and then in the morning turn the lamp back on to raise ambients for the day.
Although I do believe there are night lamps you can use that will allow you to view your snake when they are most active without bothering them, I personally have no experience with lamps though
Edit: I don't believe it would have any affect on your snake if you switched hot sides from morning to night but I would suggest maintain the 88-90 f ( 31-32c ) hotspot with the heat mat and then raise ambients of the entire cage to around 80f (27c) with the heat lamp.

Is there no way to surpass the use of a heatmat? as mine is used inside the cave it can cause thermal blocking? I'm getting a better understanding now however that the lamp is mainly used for ambient temperature, but surely it would also heat the sub terrain to a reasonable level that it could be used for the hot side? I just need a way of keeping the ambient at 28ish but also maintaining a cold side and a night time temperature without it dropping completely below recommended temperatures

ADDED - I guess I'm trying to form some kind of shopping list as I definitely need a lot more in terms of temperature moderation, for such a big tank I only have on thermostat set up the heat mat and a basking light at the opposite end of the viv which I was told to just turn of manually after 12 hours.

If you remove the shelves a day and a night lamp should work fine. The heat lamp will heat the floor underneath it and the air, but your snake will be in his hide, not necessarily sitting on top of it where the lamp has heated. This is not an issue as long as your ambients are high enough, I have no experience using only ambient temps, I use belly heat so someone else will have to provide a bit more on that. Using lamps you will have to keep an eye on humidity, preferably between 60-80% but not so humid there is condensation.
Is your heat mat currently inside the enclosure? If so, I would unplug it as your reptile should never be in direct contact with the heat source.
You said it was a bearded dragon enclosure, I assume it would be sealed but you should make sure it can withstand high humidity without molding because beardies don't usually have nearly as humid of enclosures.

I will check if the viv is sealed tomorrow, in terms of managing the temperature of purely overhead lighting, how would be best to go about it? I appreciate you said you use underbelly heat but it seems like you know a lot more than me, haha! Setting up some form of night lighting just to keep the ambient temperate at about 24 degree during the night and during the day having a ceramic light to raise the ambient temperature and directly project the hotspot? Could you recommend any equipment in terms of managing these lights? ensuring they stay at the right temperature and what not, thanks again!

Instead of heat lamps you could use a ceramic heat emitter which will raise your temp throughout the entire cage and can be used 24/7 as they put off no light
http://www.amazon.ca/Zoo-Med-ReptiCa.../dp/B0002AQCPK

No matter what you go with it should be on a thermostat to regulate the temps. I use herpstats http://www.spyderrobotics.com which can be fairly pricey but work extremely well and last a long time

Another item which can be surprisingly helpful is an IR temp gun http://www.amazon.com/HDE-Non-Contac.../dp/B002YE3FS4
not only will it help you dial in exact temps throughout your cage, but also to get live feeders to switch.
One of my girls would not look twice at a room temp f/t rat but using a hair dryer and a temp gun I was able to get the rat to its normal body temp (37c) and she snapped it right up.

Would I not still require a night like as it was my understanding that they expected a lower temperature at night? Cheers

Some people have night drops, I would say its more important for breeding, but certainly not necessary.
I've never dropped temps and all my girls seem to be doing fine.
Although, there are lights that won't affect a snake as they can't see them which will allow you to view your snake while they are most active during the night.
Depending on where the cage is in your house it may even be dark/ hard to see your snake during the day