Well I have managed to find a way to force a slightly older PHP version on the site & forums that is sort of working. I think I've resolved most of the errors but I am sure some more will likely pop up, but so far it appears everything I have checked is working again. I could still move things to another server where I have full control over the available PHP versions but that is not something I'm willing to tackle just yet.
If anything is broken, feel free to contact me about it....
