Would expect a VH sale anytime. We booked a few days ago for next Xmas. The following day the prices rose by about 3-4%. Not saying Virgin do this but many companies like Argos for Example increase prices just before a discount offer.
Always look at a package comapared to flight only/Flydrive.
eg. I have booked package next Xmas staying at Marriott Village, Fairfield Inn £599 each. Flydrive with no hotel and no car (flight only) was £671