This worked like a charm, once I'd left the ignition on before removing and replacing no 18 fuse. Dealership wanted £100 min +vatI have no idea if temperature is a problem - I live in Scotland and it doesn't really get too hot here.
follow this link - you should see that fuse number 18 of the dashboard fuses of the left of the car is for the touchscreen. I removed number 17 too and put it back in.
Peugeot 208 Fuse Box Diagram
Remove the fuse for a few seconds - put it back in and it should reset the touchscreen - that's all i did and i had no problems.