Just after a bit more advice , took this to my local dive shop to get a fill today,
Anyway filled ok as it should , guy said I had screwed the fill nipple in fine without over doing it so it was bottoming out , as some people do .
Once filled ,when he went to test ,
the fill nipple failed and had to release all the air slowly out, he did double check to make sure nipple wasn't sticking.
Now I'm wondering could this be reg related damage or should I order another nipple and repeat the previous ,he did say make sure there isn't any sh*t inside which I did already and as Magic Rat had mentioned not to have any ptfe tape overhanging the threads which I had.
Guy was great in shop new his stuff , didn't charge me ,told me of some horror stories while we waited for the fill