Rear Window leak
 

My colleague who has a 75 saloon is experiencing a rear window leak proved by the presence of water in the channel inside the boot top just under the window. He also observed drips during a shower, from the screen seal. Apparently there is movement on the rubber surround if pressed in, but does recover.

He is having woeful trouble trying to find someone in the Bournemouth/Poole area to fix it for him.

Can any one suggest a contact please?

If by screen seal you mean the rear window trim then it is just that, a trim and it is only clipped into position and has no sealing function (the rear glass is 'glued' in place with flexible sealant). The lower trim clips (I think there are 7) are however prone to promote leaking into the inner skin of the boot panel (and thus into the boot and spare wheel well) - the bit that runs across the rear of the car between the lower edge of the glass and the horizontal boot frame opening.
There is an excellent how-to somewhere on here giving you a complete diy method for cleaning/sealing these pesky clips

Try Captain Tolley's Creeping Crack Cure, worked for me.