Is this a good skim job as want some advice 

Run your hand over it, how does it feel? 

Bumpy and can see cracks under surface

Last couple of photos are as rough as toast. 
 

What was it skimmed over ..? Existing plaster and paint ..??

It was over paint and plaster correct  and he done it all in 5 hours and said that the pva would hold back distemper lol

Will this fall off once pai t is applied 

Not sure how anyone can tell you this?

the competency of the plasterer is in question so doesn’t look good from a longevity point of view but equally some sand paper might sort it?

 

Did you dry it with heaters to speed the drying process up?

does it sound hollow when you tap it?

In place it sounds hollow and no heaters on it as radiator was removed this is his last wall he done for us dont think should have him back 

I meant did you plug in a fan heater or something to dry it out?

No nothink just let dry naturaly