You can never predict what the insurance companies will say, but from your description it sounds like only superficial damage, The knocking sound would be a concern simply because if it is knocking against the tyre you might get a blow out, but it could just as much be a loose panel in the wheel arch where the nut holding it has come out.

I would get it looked at and do an estimate on the job making sure the garage knows not to do any work unless they get the go ahead from you first, then compare that to the value the insurance company has placed on the car..

There are in fact 3/4 categories of write off, some of which you can still get money from the insurance and continue to drive, below is the rac info about this, scroll down to the bottom if you want to get to the important info.

https://www.rac.co.uk/drive/advice/know-how/what-is-an-insurance-write-off/

I would suggest that the 3rd party went to see if the CCTV was working or covered that area, and if he said yes then perhaps the other party felt there was video evidence and as such had no choice but to admit liability, maybe.

" Cat N classification encompasses all non-structural damage, such as lights, infotainment and heated seats. As with Cat S cars, Cat N vehicles can be put back on the road, however, unlike Cat S cars, there is no need to re-register it with the DVLA – though you will still need to inform them your car has been written-off.

In effect, Cat N and Cat S replace the old Cat D and Cat C categories respectively, albeit with modifications to their remits.

Updating the write-off categories means that buyers looking at vehicles which have been in a major accident will get a better idea of the type of damage sustained. What’s more, the registration certificate – the V5C – will now to be marked with an ‘S’ to signify the car has been salvaged so buyers will be better alerted to cars with a write-off history." Pasted from https://www.autoexpress.co.uk/car-news/consumer-news/99750/new-write-off-categories-explained-what-are-cat-n-and-cat-s-cars

Edited by A Driver since 1988, HGV 2006 on 03/02/2020 at 18:19

Then I would suggest the insurance company would deem it as beyond economical value and give it the lowest write off rating.

Which if that is so means you will get scrap value but can continue to drive it providing it is safe to drive, so I would ask the insurance company about the category if they decide to not repair it.

I am sorry but the insurance company use their own body repair company, and they are a lot more expensive then doing it through a garage of your own choice, when I claimed on my insurance I tried to get to use a cheaper garage but they said they would not cover the cost if i did not use the garage of their choice.

But they would happy to let me do it if I did not make a claim.

Also be aware that if they say it is beyond economical repair ( a write off ) then that may affect your insurance, mine was given that rating and I continued to drive it, a garage told me it was still safe to drive, I got into an argument with the insurance, telling them that the brakes worked, the steering was good, electrics etc. It made no difference to them, the car was still good a year later. I told them it is not a write off if it is still perfectly drive able, body panels are expensive mate which the insurance company will only get from the main dealer, and will not accept parts from anywhere else, not even euro parts.

Edited by A Driver since 1988, HGV 2006 on 05/02/2020 at 22:08