Unfortunately, the old saying 'you get what you pay for' is seldom applicable nowadays and we see that in today's financially problematic times, prices will be inflated more and more- for many reasons, overheads, fuel prices, etc... But I would encourage that research is the key, along with word of mouth referrals where possible and of course ensuring suitable qualifications and reliable products.
As far as enforcing authorities questioning what is not VFM, not a good idea UNLESS all the facts are known about the higher priced, company, it's reputation and the quality (manufacturer) of the parts quoted - and what it can be measured against assuming all things being equal. Even then caution when commenting should be observed.
On the other side of the coin it is not nice to see people being duped (in some cases) into paying higher prices (so they can sleep at night) for something equally as good that with a bit of savvy could cost less and fulfill the same purpose.