Dont know if its still on, But if you go to Debenhams, they are having a 25% sale and if you open a store card they give an extra 10%. In my local debenhams that is what I did the other day and they had a sunglasses hut thing in there selling ray bans, oakleys etc.
Probably the cheapest online retailer for Oakleys, just nip down the shop try them on then go back home and order
if your are interested I may be tempted to sell my Oakley splices in silver with gold with fire iridium lenses very tiny scratch on one lense bit of scuffing on the frames
How much you looking to spend? Got some Oakley Twentys I'd be willing to part with. Silver "Full Metal Jacket" frames and blue "iridium lenses". Exactly the same as the following: