Hi guys, newbie here! (Be nice )

So as I was driving to work this morning, I got bumped into by a blue mini in the backside. Later the day when I took it to a bodyshop, they told me it'll be replacing the whole rear bumper if I go through insurance and has yet to give me a quote. The guy at the shop told me that the bumper has lost it's structure, which caused the crack
I was stupid enough to not note down the reg number of the mini myself :bangthe one he gave me was unregistered) and forgot to ask which insurer he was with and the chances of him picking up his mobile is very slim (he could've also given me a bogus number for all I know). So I'm still contemplating on going to my insurer (I'm still a young-ish driver so I dread to think what my premium will come up to!)
With my MOT coming up in Sep, I think I'll need to fix it soon. I'm just wondering if there are any other (maybe) DIY options or cheaper options about?

Cheers!

For the MOT, so long as here are no sharp edges and it is not about to fall off - it will be fine.

try putting his number into google first
it might come up as motor trade or something
failing that send a text saying you needs his details or you might be willing to have it repaired without insurance being involved
if text goes through and its ignored you could approach the police with a view to leaving the scene of an accident
just be cool now though accidents happen

If it is just the bumper that is damaged, the cheapest way is to find a Panda that is the same colour that is being broken for spares and fit the bumper from that top your car. It should be easy to change the bumper with a few basic tools or a garage/bodyshop should not charge more than an hour or twos labour to do the job.

It is possible the crash bar behind the bumper is damaged aswell, but this just unbolts so the same thing can be done.