I think you'll have to go with white or whatever looks best indoors in those rooms. You can always think about getting the windows colour bonded at some point instead of replacing them. Then you can choose any colour for those inside and out! You can paint UPVC yourself - All of our windows inside are painted the same colour as the walls in those rooms so that the windows blend into the walls. They were dark brown / mahogany ( vile ) - Outside they are all sage green. If you're going to paint the frames inside which will brighten the rooms and let you have whatever colour shutters you like, use Zinsser 1-2-3 primer and then paint away.

I know this thread is slightly old now, but I've just used Bedec msp paint on the outside of my upvc porch and it's amazing stuff! Would highly recommend (took me years to pluck up the courage to try it) I spoke to the company's rep and got advice on what to use. Clean with an anti-fungal cleaner (NOT sugar soap as that leaves a residue) let dry. Scour with a green scoured pad OR a v v fine sandpaper which is only to take off the sheen and not to scratch the plastic. Wipe clean with water and let dry. Apply the paint with a brush not too thickly or thinly. Wait to dry 2-6 hours then repaint. Takes one month to cure. My experience - I did black over brown and 2 coats was fine. I found all the brushes I tried (not real hair ones) did leave some marks but I think that's due to the paint. Don't go over it too much in one spot. It's quite thick - plasticed when it dries so work quickly. Less of an issue inside when the sun isn't heating it up of course. Water based so cleans up easily and good range of colours. No primer required so v speedy job! I debated whether to try this or the bullseye 123 primer etc but I'm glad I went for this as it was a lot less work and it looks brilliant.

Thanks both for your help, my only issue with the white apart from the cleanliness is fact that we would have to stop at the edge of the brick and then carry to paint the top part white too, and I actually quite like the original stone colour. That’s why I was thinking a grey beige to kind of blend with the original.. but then it’s committing to carry on right through the porch and where to stop😂🙈 Does anyone know if you can clean/strip paint off brick? Doubt it as assume would soak in

Have no experience personally but in answer to your first, you can spray outside only or both sides.