Car damaged while parked unattended - do I contact my insurer?

Hi all,

I went back to my car after work to find it with a few dent and some minor scratches on both passenger-side doors.

Two body repair shops quoted £350-500 depended on whether we'll paint over the entire side of the car or just the doors.
What's unfortunate is that I had arranged to exchange this car for a smaller one plus cash this coming Friday.

I have comprehensive insurance, with a compulsory excess of £120.
No NCB potection but I can add that for a very small fee (spoke to the insurer) if it's worth it.

Been reading up on the policies and a lot of stuff on the web only to confuse myself further.
I guess my question is, would it be worth it to put the claim forward or just eat up the cost of the repair?

From what I'm reading, it seems that after spending a lot of time on this, I'll still end up paying possibly more than the cost of the repair one way or another (present and furute car insurances will make sure of that), which is quite annoying seeing as I've been paying them all these years for "nothing".

Do I have it all wrong?

Thanks,
CT