Really sorry to see your misfortune.
I had a similar experience last year.
The boot lid you've got is an Aussie one. They're different to the UK bootlids. There are three common bootlids - 850, Aussie, and Rover. The 850 bootlid looked just like an Aussie one in style, except the number plate holder was much wider. For appearances, you really want to stick with the Aussie bootlid. That said, they're getting hard to find...
The other parts you've listed... From the photo, I'd be surprised if they get replaced. The bumper, sure, but the overriders and nerf bars may well be re-used, just installed on the new bumper. The boot hinges may be re-used - mine were. That said, £49? You'll get them cheaper than that locally.
The tail light doesn't look damaged at all. Mine was smashed, but, like you, I have the Aussie 2 screw tail light. You can't buy them new anymore, either - the UK ones are all 3 screws (which Aussie cars had for a while). As long as the baseplate - the chrome part in the body - isn't bent (and mine took a direct hit without bending), it'll be fine. Maybe new screws, but I got the impression they're easier to repair than the 3 screw bases. The only problem is that the new glass available for the 2 screw lights doesn't last as well as what you've probably got on there...
If your repairer has any issues, I'd definitely refer them to one of the local mini businesses.
They're going to have more chance of having exactly what you need than anyone overseas. Going overseas for this wouldn't save you money (even if it did, it's not your money!), it'll only cost you time.
And your plate..? It doesn't really look damaged... I didn't get a new plate after my crash. Maybe you'll be able to keep the New England plate?
