[victorgte]

I bought a back box for less than £60 and fitted it myself. Not difficult but requires patience.
Day before put some penetrating oil on the 2 nuts on the clamp to undo it easily.
Buy a new clamp. It’s so much easier especially if the old one is rusted so bad you have to cut it off.
Original ones were held on with a metal strap and hangers. Aftermarket ones tend to just have hangers welded on which attach to the rubber hangers.
A rubber mallet proved useful to tap the 2 sections together and some exhaust paste to get a good seal once it heats up.
I put my car up on ramps which have proved useful for many jobs over many years.