Bob has repaired crash-damaged trikes before now, as I've spoken to him about it in the past. IIRC his main concern was whether the main tubes and cruciform castings are crack-free and still true as per Arellcat's post, and I think one of the ones hanging in the Norman Rd workshop when I first went there was beyond repair as it was twisted during a crash. The frame bonding is a Loctite product, and the minor units can be unbonded - when I bought my trike secondhand, Bob unbonded the nose, shortened the tube, and rebonded the front end for me, so the frame could be shortened for you, assuming that it's not beyond repair. It's probably an application of heat, rather than clever chemicals, but Bob should be able to tell you. The joystick casting is different these days, and the 'handlebars' are alloy tube rather than a shaped casting, but the main tube should be the same. The steering universal joint is not up to huge loading forces, so you may need to check that that wasn't damaged. The rear hub is custom, based on a wheelchair hub with the bearings in the casting on the rear of the main tube. You'll need to check whether the axle through the casting is ok, as that's also custom.
Bearings, seat rubbers and the UJ are pretty much over-the-counter parts which can be had from companies like Farnell/CPC, or possibly your local engineering workshop. Bob would probably be more expensive, but going to him has the advantage of his experience building the machines. I would be looking to have a chat with him direct, as an opinion on whether the trike is repairable in the first place might save you a lot of trouble.
