Not sure if they sell them in the UK, but herpstat is a good thermostat brand. I have a herpstat 2 and 4.

For heating, you can replace the basking bulb you have with a CHE (ceramic heat emitter) that will emit heat, but not light. It can be controlled with a dimming switch to adjust power, just like with a basking bulb. If you don't already have a temperature gun, you might want to get one. They are cheap and can be used to read the temperature directly below the basking spot and on the cooler side of the tank.

For my snakes, I use an under tank heating pad controlled by a t-stat, on some species, I use a basking setup like yours or a CHE for nocturnal animals that need heat at night. I also have an oil-filled space heater hooked up to an industrial t-stat that keeps my reptile room an acceptable temperature (for cool side temps). That runs 24/7.