Perma-white peeling off

Just painted my bathroom and am a bit worried about the paint.

The walls were bare plaster, done in Feb but not decorated until now. I was advised to seal the plaster first and used Gardz, waited 3 hours and then painted with Perma-white.

That was a couple of days ago and today I went to remove the masking tape I had used round the spotlights. When I took this off (after lightly scoring where it met the paint) it pulled large chunks of paint off the ceiling, it was like it hadn't stuck. The same thing happened around a few of the other masked edges too.

Should I be worried about the paint not having stuck properly?

Hi,

I may be wrong, but I don't think you should be overly worried about the paint peeling away, but there are a few things to consider!

I have seen stories that Gardz may be too good a seal on new plaster. Moisture would not be able to escape from the drying plaster, and this could cause bubbles in the new paint.
As your plaster has been drying since February, this is unlikely. However if the bathroom has been used in that time, a fair amount of moisture could have been sucked up again!

If the plasterer did a really good job, then the plaster can sometimes be too smooth to accept paint - imagine if you were painting glass! A light sanding first may have helped.

A couple of mist coats would have been good enough and probably have been a good deal cheaper than Gardz.

Three hours between applying Gardz and overcoating is the absolute minimum recommended by the manufacturer.
A longer wait may have been better.

And finally, masking tape should be removed as soon as possible after painting. Frog tape (low tack masking tape) is far better than plain tape, but should still be removed immediately after painting.

It's possible that the paint hasn't fully adhered to the ceiling, but there are many different circumstances that could lead to that. Not all are foreseeable!

Bathroom hadn't been used so shouldn't have been too moist inside.

I used Gardz because it was recommend by the local diy shop, usually I'd mist with cheap emulsion but I was trying to get it finished a bit quicker.

I was using frog tape, the bathroom needed an extra coat on it which is why I waited to take it off, it was looking a bit patchy in the corners.

Ill patch it in and hope for the best.

Frog tape is very good, but the instructions do say to remove immediately after painting (for best results).
Apart from that you've done everything right!
Some things just happen!
Try a patch and see how it looks