[JeanMcaleer]

I'd say that painting MDF can be a pain if you don’t prep it. It soaks up paint like crazy if it’s not sealed. I used an MDF primer first, then just painted over with the same emulsion I used for the walls. That way, everything matched perfectly. If you skip the primer, it’ll look patchy, so don’t skip that step—it’s worth it.
Oh, and if you’re still sorting out materials, I’ve come across some decent options online for MDF wall paneling at https://mdfskirtingworld.co.uk/ that might be worth a look.