Intermittant idle issue advice

Hey Guys!
Well, had a great run out today and had so much fun, I still have a smile on my face!
The run went well. Engine sounded awesome.
I still have that idle/tickover issue however not as bad as it once was.
It always seems that after about 45 minutes of "spirited" driving where everything is perfect, I'll pull up to a roundabout or traffic lights and the engine will just cut out.
I then restart the car and drive off fine.
It seems that after around 45 minutes, it struggles to hold the revs high enough to prevent it cutting out.
Up to this point, it's perfect.....does anyone have any thoughts what could be happening?
I've got in my head that it's something to do with the fuel and the carb getting hot.....would that be a thing?

Gareth.