Thanks James - I am using 'Motherboard Monitor 5' which I downloaded a while ago to check the CPU temp.
When I installed the cooler I decided to use the switch on the back instead of the auto-detector, and it was already turned up to maximum.
I'll try taking one of the sides off, I have a PCI fan as well that I'm not using.
Anyway it's down to 66C now so looks OK.