Any advice welcome, the last owner has I assume sprayed the door in a non matching paint. I don't know why as there is no sign of damage, only problem is it's getting more noticeable over time. Any ideas or do you think I need to take it to a bodyshop

Light sand with 800+ up to 3000 wet and dry in the area of concern. if possible get back to the original colour and relaquer if possible

6 hours ago, stevet125 said:

I assume sprayed the door in a non matching paint.

The over sprayed paint won't have bonded with the factory paint. You will be able to remove it just by using a cloth soaked in IPA and a bit of firm rubbing.

Have a read of this thread regarding the use of IPA to clean off paint:

 

Depending on your skill and what you want to end up with I would try a bit of both replies. 

You may be able to remove the odd paint with light sanding using fine wet and dry paper or if your not confident use T-Cut. A clean up with IPA will certainly remove any grease and possibly the paint ready for painting (does remove paint of a plastic washing machine). 

Then as it's a relatively small area you could mask and paint the whole panel with a couple of rattle cans colour matched and clear top coat. 

Trying to blend the patch in without the correct kit will just achieve the old result. 

The sanding and cleaning may reveal the reason for the odd repair. 

Thanks will try the ipa first as I have it in the workshop anyway. Although my wife did think I was going to rub pale ale into it 🤣