dear Mr Van Nuil,
i am sorry that you have not had a reply. there may have been several readings of your original post but they may not all have been in the uk o even n the north west. i personally have only just read your original post and this one. As you have logged on, I do not have your direct e-mail and thus aplogise for answering this way.
yes I hold a g4 license and have a background n electronics but these days of surface mount components, repairing and fault finding down to component level you require more specialised equipment like specialised extender boards to mount the pcbs in suito to gain access, a full esd work station an soldering iron station with specialised tips, maginifing glasses and headsets and the full service manual for the radio.
for example, one of my rigs developed a none transmit fault and as i do not have the above, i sent it off to one service company who located the fault to one board but did not have the full repair extender cables who then the rig off to another company whohad the full set up. the fault was a solder joint which only showed up after 6 years!!
talking to one repair shop, i find that big names also use them for repairs as its not cost effect to have a workshop set up not only for the new radios but some of the older ones.
now to fully answer your question, I do not know of anyone up here who might be able to help you however I would suggest that any that advertise in radcom or sprat would be worth talking to. i have talked to Castle and Adur comminications were very helpfu, hourly rates and postage etc was very reasonable.
i know that the listeners are also vital to this good hobby of ours and i wish you many more hours and years of enjoyment and maybe have the pleasure of talking one day to you.
Chris g4lds