Fuel pump, injectors and governor overhaul

[Tractorbob3]

I think it's time I did my 62 Super Major a favour and get the fuel side of the works sorted out. It's had a hard life and when the black smoke clears and I get the revs to calm down, I can see the bush inside the governor is worn one-sided and needs to be replaced (which looks easy), but I can't deal with the Simms (not Minimec) pump and injectors. Can anyone recommend a supplier who can either overhaul or offer serviced exchange items, please? Mid/southern UK would be handy, but if the quality is there and the price is right, I'm happy to pack them up and send them further afield.
Thanks in advance for your help ...
Regards - Bob