Norton Commando valve seat replacement

The inlet valve seats on my old Mick Hemmings big valve head have receeded & need replacing.
I suppose the easiest way would be to send the head back to him in the UK (I'm in Canada) to have it done, but that would be too easy!
I've had seats replaced before on a standard head. The local automotive shop (which is no longer around) welded a bead to the inside of the seat & they fell out when the weld cooled.
I don't know how they replaced the seats. I assume they found some replacement ones that were the correct interference fit from a supplier, heated the head, cooled the seats & pounded them in with a suitable shaped drift in the valve guide.
Is this the correct proceedure for replacing valve seats on a Norton heads?
Where would you obtain valve seats?
Is there somebody in the USA that can replace valve seats?
The local Serdi guy said it would be too expensive to fabricate a holding device for the head & macine them out.

Leo Goff at Memphis Motor Werks can replace the seats and recondition the head . He is a Norton engine specialist. Do some research on him and you will find that he is the MAN when it comes to Norton engines.

t7275tr said:

Leo Goff at Memphis Motor Werks can replace the seats and recondition the head . He is a Norton engine specialist. Do some research on him and you will find that he is the MAN when it comes to Norton engines.

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We attended a seminar by Leo at Barber. He certainly knows the right way to work on a motor. And has the right tools. Pounding in seats works great on something you don't care about but has no place around a Norton.

Carefully welding a bead around the seat itself will shrink it and should allow it to fall out, I have done this also on taper roller bearings in headstocks where there was insufficient clearance to drift them out. I don't think pounding should be required to fit new seats if the head is at the right temperature and the seats themselves are cooled. The seats will have to be recut (not simply re-ground) once fitted to conform to the angle of the valve guide. Norvil in the UK sell the seats, 17 pounds each in the catalogue that I have to hand.