One of my injectors is spraying out petrol when you turn the ignition key - think one of the seals inside the injector has gone so the seal isn't petrol/water tight for want of a better word. Has anyone got any ideas? is this is an expensive fix? just seems to need a new rubber gasket I think but not the most mechanical.
It's a bravo 1.8HLX

A new injector won't cost much from a scrapyard and there are loads of Bravo's in the scrap yards now.

did you disconnect the injector to make sure it is not being opened electrically ?