Plasterer

The pva can be mix with water is about 4/1, four time pva and one time water, if the pva is thick, if is already deluated you can paint it straight away, or thistle bond-it ready mixed plaster & bonding agent, 10l tub, from british gypsum, one tub should be enough or can cover about 45 m2, you must let it dry properly, to dry can take about between 3/8 hours summer time, if is cold between 12/24 hours, after that we can plaster it.

If is the bubbles big and when you tik on them is sound like kraks and around it appears crack is when didn't prepared properly the surface, and the plaster it can happen to came off, if is smoll bubbles marks and don't look straight is the plasterer unexperienced.

K-rend is one of external render, to make difference between them should be specified which is the second one: sand and cement, silicon render, or oders

Fixer

It will look properly done, been plastered in full