Is my vivarium good enough?

[Inky]

I'm unsure because there are so many different opinions being thrown at me as to what I should do. I am really unsure if this set up is correct, particularly the in-cage lamp, of which is protected by a guard so the snake doesn't burn himself - as with the UV light.
This vivarium used to belong to my bearded dragon who sadly passed away last year. I've had this snake since September 24th 2015 and he is currently 2 years old, so far I have noticed absolutely no health issues, he's one healthy boy and I want it to stay that way.

90% of the photos I see are of snake vivariums which are completely glass fish tanks with a heat lamp on top of it. I feel as though I'm doing something wrong and I've been thinking of getting a new vivarium for a while now along with a new setup all together. Though if this one is fine then I'll keep it.

Here are both sides of the vivarium.

Bare in mind:

- I only turned the UV light on to brighten it up a bit for the photo. I only use it during certain times of the year where my bedroom is dark. I only have 1 window and not much light gets in during those times.
- The cardboard hide is different to the other one, yes. An identical black hide box should come soon - I just wanted to get one first to see if it's the right size.
- Currently there is no heat mat, but I do own on which used to belong to my beardie. I didn't want to use it because I can no longer control the amount of heat it emits and I was afraid it would burn the snake.