I think you need to take a look at the Trademark register. There are two entries for 'a quick sale' See here:
http://www.ipo.gov.uk/tm/t-find/t-fi...atusselected=A
I'm no trademark expert (perhaps Beasty can give some insight on this) but it may be significant that the original trademark application for the term 'A QUICK SALE' for a WO trademark was withdrawn and the only trademark registered under term 'A QUICK SALE' is for a DW trademark.
I have always thought that a WO trademark gives exclusive rights to a term wheras a DW trademark is for simply trademarking the term in the form of a logo or image. It would be very helpful if someone with a legal brain could clarify this situation. In any event I would strongly recommend that you take some legal advice on this before responding.