My 2002 P38 4.6 Vogue has decided this morning to drip coolant into the drivers side footwell..... the dreaded heater matrix o rings!
I have found a specialist in central london 'Central London 4x4' who have quoted £320 to do the work.... they say that they have done hundreds and can do the work without much disturbance to the dash......
Dont know if anyone has dealt with them, or if anyone in London needs this work done..... and if they are capable (or not) !!!!
I will post a result to let you know the results after the work has been completed!

Well..... they did the job superbly!
Highly recommend this chap!

have just done this job myself, first find out which pipe going into the heater matrix is leaking. the pipes are held in place by a clamp which is secured by one screw which is between the two pipes, undo this screw(have some towels ready) this will release the clamp, gently remove the offending pipe backwards(just a little so the water trickles out), this is when you will need the towels to catch the water, once the water has stopped remove the pipe, the o ring will be on the pipe, simply remove the o ring and put on a new one this cost me 20p from a local car parts shop,make sure you get the right size and get 2 just in case. replace the pipe and tighten the clamp, refill the expansion tank start the engine and check all is dry, sometimes you may need to tighten the clamp a little more.All in it took me 30mins and cost 40p. hope this helps good luck.