Thanks mate you're a champ. The last thing I want is to do a divinci piece of art and find I sneeze and its all gone. I will investigate the enamels you're talking about.
One thing you stuffed me on is roughing the surface to enable the paint to key into it. My wife suggested that and I told her to go shopping 
I hate it when they're right. I'll have to put you on ignore so she can't read your response.
Thanks again for your advise and look forward to my next attempt.
Btw with acrylic, if you stuff up, its a damp clothe and start again, enamels not so easy?????
Acrylic paint can always be cleaned off with water, it is never water proof.
You need to clear coat over the top once you are happy with it to lock it in, then you can wet rub the clear to smooth it.
Yeah you need to lightly sand any surface before applying any type of paint.
