Bathroom tiles or multi board

[GreedyCymraes]

Really allergic to mould and have discovered that the black grout in bathroom I've just inherited is not in fact black grout but mould covered grey grout. 🤮

So. Now a room that wasn't on my list has to be dealt with, with almost no budget.

Any suggestions welcomed (bathroom suite is fine) just walls (all tiles, every inch!)

Would one of the professional tile and grout cleaning companies be a cheaper option than retailing or replacing with upvc panels?

With no budget, I'd first look into stripping out the grout, and re-grouting it.
If getting the old grout out will trigger your allergies, get a handyman style person to do it for you.

Will I risk the mould coming back this way? I don't want to take shortcuts and if i have to I will retile or resurface. Just will mean forgoing the new sofa or other work being done

If you have the grout cleaned or replaced professionally and properly, I would have thought you keeping it clean and bathroom ventilated would keep the bathroom mould free, or worst case would give you time to save up to renovate.

https://www.ocado.com/products/cillit-bang-black-mould-remover-foam-spray-272697011
I used this on my black mould tiles when we moved into our new house. It worked very well, but needed a couple of goes. Then I used it once a week to prevent mould returning.
If you weren’t planning on replacing your bathroom (we knew we would be replacing ours within 6 months) then give it a go first, and maybe regrout the tiles if it returns before going to the expense of replacing them.

The mold won't come back any faster on properly done regrouting compared to new tiles and grouting. So, if you were going to clean and ventilate to control mould in a new bathroom, the same will be needed in a regrouted bathroom.