I would attempt this job myself. Take a scraping of the paint colour to a paint shop and see if they can match the colour for you.

I would do it myself. Scrape some more paint of and have paint made by Bunnings in the right colour, sand and clean it before painting. With wood I do often enough patching up and it gives quite a good effect, I wouldn’t recommend patching up with walls though.

keep it as a reminder. Or simply repaint the whole door (the rest probably needs a touch up anyway).

You might be able to colour match but you are probably better off painting the whole frame so you don’t notice a patch job. If you can’t find a local painter, try local pages on facebook. A mums group or community page that might be able to recommend a painter or small job worker in your area that people have used and can put a good word in for.

yes it can be matched but yeah you will see the difference as soon as the room is flooded with light.

You may be able to do some of the preparation work yourself such as removing paint that is falling off, then sand the door and frames. A good painter will accept the job. Bunnings run free workshops demonstrating how to fix things. You may be able to do the repair part of it yourself, and if you aren’t confident you can do ther actual painting to you own standard, aks a painter to do it. Make sure the painter is licenced and has the relevant insurance cover. Get more than one quote. Some are a “rip off”

DIY is also a good idea and on a little area should be a good project?

Painters should take on little jobs and big jobs.

I am sure they would, but be warned that even if the paint matches it would still look untidy. Having areas freshly painted and brand new against older paint jobs. We have tried to do a wall etc here and there in our house and it is so obvious to all that look at it.

I think if one did, it would cost a lot of money. Could you perhaps go to a few DIY workshops at Bunnings or similar and try to do it yourself?
Sometimes we can manage a very reasonable job if we just try.