Try these guys Joe, Hogg diesel injection services.... He has a good reputation according to my South yorks VOSA counterpart.
Essentially all fuel injectors are pretty standard, just different flow rates. They are not made by each car manufacturer for a unique fuel injection system and they are usually Bosch / Delphi units.
It may be more cost effective to get them reconditioned on a surcharge replacement "like for like" via post or even take a drive down. Give them a call