First of all you need to find out whether the master cylinder is a Girling part and/or the servo is a Clayton Dewandre part.
If you had a workshop manual for your model it would give this information and what steps to take to overhaul (ie fit new seals).
You might not be willing to undertake this work yourself, but if you can provide your mechanic with this manual he should be able to follow it (assuming he can understand basic English)
You need to find out what model your vehicle is (see the plate on the passenger-side wheelarch or door pillar) and you will need this information to ensure that parts are correct.
If you have the original UK registration paperwork the information that you will require will be there, too (and maybe in your French registration documentation) then search for a workshop manual including brakes. It will save you time and money in the long run, otherwise you will be guessing that the parts you need are correct.
This
might be what you want, although it might be too early for your vehicle:-
Bedford TJ/TK. Service Training manual.TS.508.Steering gear,front axle,brakes.April 1961.130 sides.
From:-
http://www.mark.clubaustin.co.uk/commercials.htm
Contact them with your vehicle details and see whether they have the correct manual.
Try these people also (just an enquiry at this stage as you don't know exactly what you need):-
http://www.bedfordgenuineparts.com/C...1DAAD88313.htm