Hi ive broke the top of my handbrake gaitor ,does anyone know where to buy a replacement ,thanks

You have 3 options...

1. Go it your nearest fiat dealer and order one.
2. Buy one off eBay (there is just 1 being currently advertised for about £26 - that's the whole thing rather than just the top slidey plastic bit).
3. DIY replace the plastic with other similar flexible plastic (others have done this).

Hope that helps.