Need help heating Pacman frog tank

[hagarthefish]

I live in the UK and we need extra heating. I also use a heat mat on the side, but as you say it's not enough.
I use a 100 W ceramic bulb in a dome above the tank. I have this working with a dimming thermostat and set it so as the max temp on the substrate is 82 deg.
It's not the cheapest method, but I find it the best, hope this helps

[Aliens]

I found for my pacman frog in my 10 gallon I get away with a 60 watt black night bulb and my room temperature is around 73F.