Thanks for the comments, I've performed a googlectomy and it appears my specific model is known for running hot often over 90C when gaming, so it may not be connected. I have also found that others have replaced fans and thermal paste and managed to get them running lower so it's been worthwhile looking into! Apparently dell are pretty pants at laptops so wish I'd have seen this in the reviews before purchasing!
I believe I do have the latest drivers for each, managed to work out how to update and it said I already have the latest versions.
For refresh rate, it doesn't give me other options to the default setting. Is there another way to change this?
When it crashes, screen and sound freeze, and then after 4-5 seconds it reboots. Doesn't let me go to windows or anything, so could well be graphics related. After I posted this I got through the rest of the game day just fine, but it's done it intermittently on other saves too. Happy to try uploading event viewer logs, do I do this via pastebin as well?
Thanks