There are always differences between shops runing sales, mainly as they all want your custom so they run sales at different times, hence the huge difference in price. In woolworths deffence they normally have some great bargins on there web site.
S'funny, Gladiator was £12.99 in Woolies not three weeks ago.
It's merely to cash in those people buying a cheapo DVD player for someone for xmas and Gladiator being a perfect Dad present. Woolies is the sort of place people try to do all their shopping at once in, and are more likely to pay £24.99 as its probably the first DVD they will buy.