Doing a fair amount of driving in this heat wave has raised an interesting problem. After a long trip I am finding it difficult to select a gear and the clutch has to pressed right to the floor. However, although the engine coolant temperature stays at 87°C, the engine bay has got appreciably hotter than normal. I am thinking the clutch cable might be stretching in the heat causing the problem. So I have tightened the cable up to see if that helps.
Follow up: Did another 80 miles today and didn't experience the problem. But the temperature wasn't as high so the engine bay didn't warm up so much. Might still change the cable though as it is getting on for 5 years old and it is relatively cheap.