We can speculate, but the arbitration service is where it will be decided.
If the tenants re-plastering is rough, you should be able to claim to make it good. You should then also be able to claim to re-paint that wall. However, I think its unlikely that they will allow a claim for painting of other walls to match as they may regard this as betterment and they don’t tend to allow claims for matching, such as replacing a set of things where one is broken.
I have to say that is probably unwise to have specific colours in a rental property (particulary when you don’t know the precise original colour). When you redecorate this room, go for something neutral or, if you do decide to repaint in a shade of green, make sure you keep details of exactly what the paint brand, type and colour code so you can buy exactly the same shade to repaint in the future.
Get a new painter or go to a dulux decorating centre or crown decorating centre and get them to match it. Even if identical colour may look different if a wall opposite a window vs one nor.
Tbh different batches of paint may look different even for exactly same colour and will alter over time so repainting whole may be only way to get exact uniform colour on all walls.
As for ‘the tenant refuses’ and cleanliness.. that’s what inventory photos (at start and moving out) and arbitration via deposit scheme are for. You can charge /withhold from deposit to get cleaned to same level as shown in original inventory - even skimming over poor replanted work will also create dust/a mess (unless your plasterers are lovely and hoover up after). You will also.need to wait for replaster to dry before it can be painted so will have extended void period so can try and claim for that