I've just had another look at it, when trying to do a fastboot format it says it has filesystem type ' ' and is unable to do this. going to adb shell and trying to run mke2fs, results in a blinking cursor like it is trying to do something, but ultimately gets nowhere.

Sorry for taking so long to get back to you, I forgot my account details. it fails to format the /data partition because it's unable to mount it, for whatever reason.

I should mention that I originally tried twrp but when it booted into it, it attempted to access the /data partition and tried to mount it automatically on load, couldn't, and then restarted the phone. I was only using CWM because it didn't do that.

I was using clockworkmod 6.0.4.5 by the way, installing the kernel went smoothly, but upon restart it got to the google screen, then rebooted, and then booted itself into recovery again. It's now at least showing up in adb with the recovery tag, which it wasn't doing before

Yes through fastboot, and yes I also upgraded bootloader and radio at the same time. When flashing userdata, it would sometimes hang on the erasing 'userdata' command and I would have to reboot back into fast mode, where it would usually work fine the second time. I'll give this custom kernel a try right now!