[bobfromhuddle]

+1 for this. The first job is to stabilise the system by fixing critical bugs.

As you're doing so, move all those queries into one big fat DB class, and when you spot groups of related queries, split them out into their own classes.

The next priority should be to get rid of the PHP from the DB - if need be create another huge class with a zillion if-else statements.

You need to modify the code to simplify it. You don't need to improve the design, you just need to dumb it down until you can understand where all the parts are. Stabilise, simplify, then refactor.