Tried another update of the long out of date website software again yesterday and the forum failed to load so had to revert again.
Technically I have to update the php operating system on the website which is long out of date before I can update the similarly ancient forum code which runs under the php.
Limit of my knowledge I'm afraid will do some research.
Well done Chris, It's all a bit beyond my knowledge limit too!
I can just about alter some simple text in the code on my pages/site & that doesn't always work!