Hi John, Appreciate the advice and comedy!
This one says 'Overpaintable': https://www.everbuild.co.uk/products/building-supplies/pva-and-sbr-bonding/501-pva-bond/, is that still not ok?
Let's move it forward. If I can't use PVA, what can I use? Also - given it's not a 'liveable' space, the...