I have had the power steering pump reoplaced on my 2002 skoda superb and it still whies on full lock. Any reason for this.

The tensioner and belts have been replaced

Has the alternator pulley been checked? If its seized it will cause the belt to squeal on full lock.

Looks like an expensive bit of miss diagnosis, oh dear.

Deffo the pulley... Had the same issue a few times, easy to replace.

Check the fluid level isn't low, mine did this till I topped it up.

They do whine on full lock iirc, if it's a squeal then you have a problem, I think what you are hearing is the pump exhausting itself so it doesn't blow one with too much pressure.