It's quite short sighted of them, because by providing better service then they might actually sell more.
Clearly PSA don't consider that to be a priority any more.
I have only encountered exceptional customer service from three Vauxhall dealers... Andy C when he was at Drive, the people who staffed the counter at Stevens Vauxhall and a dealer elsewhere whom I bought a load of bits from via Carpartsconnexxion.
Omega 2.6/3.2 production represented a fraction of the GM utilisation of that engine. A further rummage suggests it was used in a selection of SAABs and Cadillacs, (and therefore quite probably Buick as well), all of which were sold in Europe and the UK.
Regardless, given the idea that a genuine sensor should be better than an aftermarket alternative it does at least give people the renewed option of sourcing genuine.
The second link in my post in the Test Zone is to purchase any available parts from a GM dealer in North Carolina iirc and includes the ability to have an item shipped globally.
Even if it lands on the door at twice the advertised price, it will still be cheaper than two cheaper sensors of unknown quality. The shipping time will probably be quicker too if the likes of ATP are anything to go by.
And let's face it, a company isn't going to ship a small order for free unless they're making it up on the order, which effectively means that either the part isn't what you expect or the shipping will be as slow as molasses.
And as it goes, Ian Allan in Virginia Waters is an Official Chevrolet dealer and GMPartsworld in Cannock should theoretically be able to order any available GM part.