Roundie - thanks for the tip about Vanquip. They're in Mansfield - not too far from Mad Matt, but about a 50 minute drive from here (unless you use the motorway, and, to be honest, it's too loud in a 100 zone!).

Working from home, it's not the sort of thing I can do on the way to work - it's time off.

Which is an odd thing to say on a day like today, but I'm working the weekend...
I went to the guy at Ipswich this morning, he looked at it, and told me to get a panel beater to weld in another parcel shelf (just lapped, he wasn't worried about fixing to the outer shell), or similar (equal or thicker gauge) steel... He was pretty relaxed about it - not stressed about the structure at all.

But if he's willing to sign it off as a 'less strong' (wish to be kind here) design than one might expect, then I'm not going to argue and tell him to fail it! Don't worry, I'm not going to go dodgy on it, I'll get it done as strongly as I can (I'm thinking about adding a thick piece of MDF cut to shape on top of the new steel instead of the masonite, too, as a 'one day maybe' speaker board, and extra bracing - will fix the belts through it), though I'm still hopeful of avoiding repainting three panels... The certifier said he didn't care if I had a Clubby shelf or not, as he'd still have to do the rest of the anchor point (and I'm sure he's thinking the belts, too - but if someone else is doing the other panelwork, they may also put in the holes for the belts, with me buying off the shelf items). I still said I'd try and find one from a Clubby...

Makes too much sense not to try.
Unfortunately, no replies on my 'Wanted' thread yet, might have to ring Mini Auto and find out if they know where I might find one... It can wait until Monday! It'll be beer o'clock for Ken. At least I've finally done something.
