Ok. Looks like we came out the other side cleanly enough.
I did find a couple of issues after the upgrade but, but on reflection, I suspect that they weren't related. In the Family and Friends section of the Evolution department, an error in my config table was preventing the discography tables loading at the bottom of each article. Sorted that.
Additional security has been placed on the file upload processes too, offering just a little more protection. This was pre-emptive rather than reactive.
I'm aware of a glitch in the scrolling gig-list, as it's presented in the Forum, which is causing certain accented characters to display incorrectly. This is a little weird, as the same code runs perfectly fine on the Archive homepage. I shall go away and scratch my head until a solution falls out.
If anyone spots any other 'anomalous behaviour' please do let me know.