Can anyone recommend a good duel digital thermometer?
I have one of the stick on ones at the mo and realise how awful they are.
The basking light is on a thermostat dimmer, so it does it’s own thing.
It's good that you have a dimming thermostat for the basking light. Does that display the current basking temperature as well? If so, then you can rely on that for basking surface temps and perhaps get another digital thermometer for the cool side so you can see the gradient. https://www.amazon.com/dp/B0017N8W90/ You could also pick up a temp gun so you can spot check surface temps in and out of the tank. https://www.amazon.com/Nubee-Temperature-Non-contact-Infrared-Thermometer/dp/B00CVHIJDK
I would pick up a second probe thermometer and set it right next to the probe for the thermostat then. That will give you a display and let you check the output at a glance.