100k recommendations

Hay folks,

Looking for recommendations for a runnable 100k (want to try and break 12 hours) please! I'm UK based but happy to travel. Ideally want some elevation and different changes in scenery, and in cool conditions. I ran Race to the Stones last weekend, and while I was happy with my run, the heat was awful and I found the route a bit dull (!). I'm a rubbish at technical stuff though, so more meandering trails than rocky mountains. Likely to be 12 month goal, so all ideas would be gratefully received.

Thank you!