Just had my alternator pulley done last week and it's been as quiet as a mouse . Got in it today and they was a high pitch squeak for about ten minutes till it faded away is this normal

no its not normal, sounds like the belt is slipping.

Did they change the tensioner when they did the pulley. I wouldn't be surprised that if the pulley was knackered then it will have damaged the tensioner. On the upside a new tensioner is only about £20 and it's a quick job to change yourself.

I'm sure they changed the lot I'll have to take it back I think , but the sound went after about ten minutes and I ain't heard it sinse grr :(