Is there any polishing compound etc I can use to improve the appearance of this ?

[They_all_do_that_sir]

​problem is the bread and butter for most of the bigger paint shops are insurance jobs with their associated overly inflated prices. So they aren't overly interested in small cheap jobs that won't be as profitable.

 

specialist restorers do a fantastic job (usually) but then you are paying for craftsmanship so ££££££££

 

That leaves the back street boys who do minimal prep and overspray everything. With that approach its best to remove and prep the panel yourself so all they have to do is apply paint