Yeah sorry folks, my very early morning brain screwed the two up. I need to sleep more.
You're right of course, it's not PHP at all.
I can turn off the setting, and I will, but I have other systems on this server that are expecting it (but not necessarily needing it).
Having read further into it (mysql isn't my thing) it looks like turning it off won't give any major issues and doesn't stop me doing what I need with my other systems. I'll disable it for now, but it would be nice to be up to current spec as it's not going to go away. I appreciate there may be other priorities though