You've just put your finger on the reason why so many people want to be able to service their regulators themselves, instead of having to risk it being done by numpties at the dive shop
A lot of people I know just don't service their regs - they consider it unecesary and risky. A lot of others bypass the shops and send the regs back to the manufacturers themselves, just be be sure they get a proper job done on it. The other alternative is to put the money you would spend on yearly servicing aside somewhere, and buy new regulators every couple of years with the money you've saved.
99% of what dive shops tell you about HSE regs is unadulterated garbage, especially when it comes to regulator servicing & upgrading - they're very fond of quoting advisory guidelines as mandatory laws.
HSE regs are, incidentally, not there to "cover the butts of the businesses", they're exactly the opposite - they're there to prevent businesses from being able to put profit before safety.
I've had one regulator serviced, once, by a shop who I trusted to do it. I don't know that I'll bother doing it again - Someone in my club had an identical reg used on 100s of dives, Nitrox as well as air, never been serviced. Finally sent it in for one, asked about what condition it was in, was told it might have been brand new for the condition the O-rings etc were in.
You might want to consider going to
http://www.airspeedpress.com and buying yourself the book about regulator servicing - they're publishers OF phenominally good diving books. Their divelight companion is frequently reffered to as "the bible" by the HID dive light yahoo group, and I've lost count of how many people have recommended their Oxygen handbook...
Even if you don't want to service your own regs, they tell you what the facts are about servicing and the like.
Bit of a rambling post, this, now I look back over it.. Oh well
If nothing else, ask other dive shops for their opinion. And consider asking the manufacturers as well.