We bought our Quantums a few months ago off Mark Powell - no issues with either of them as yet, and I see that some of the shops that had frozen their stocking of them have started selling them again too, so I would hope you are ok to buy them now.
Of course, I would getr them off a dealer i trusted to help me out if something did go wrong - just in case. A hint - this may not be the cheapest place
Lou