Cheers Dave. In a way it all feels like fate - if it hadn't been for the first place doing such a shocking job, and a rubbish bodge, I wouldn't have found out how bad mine was, wouldn't have found this garage, and wouldn't have ended up finding out about @Grant amazing shell.
Wouldn't have ended up spending as much either like, but at least now she's good for another 20 years (fingers crossed).