Surface spread of flame + HMO's

[Big T]

I just wanted to get an opinion.

In a HMO is there a requirement for a class 0 paint in the protected staircases?

I have just read a document by west mids fire and it only recommends having no Highly combustible linings like Poly tiles or floc wall paper. To me that isn't recommending not using class 1 it's being specific about certain types of finish. As long as you aren't using class 3 in these areas would it be acceptable to use a class 1 finish in the hall way and stairs?

[kurnal]

Best practice guidance will point to class O or class 1 depending on the risk.

I interpret that as Class O for flats, and for higher risk, taller, lower quality HMOs, dropping down to class 1 for low risk, low rise high quality premises. Never any class 3 or painted flocks etc in an escape route.