I found a super-cheap budget set for just £11 on eBay, but these turned out to be for a left-hand drive car and are the exact opposite profile of the ones I need here in UK so would not fit. They were from a UK stockist too, who didn't seem to know the blades were wrong, this was obviously the first set they sold for F10 or maybe mine were a fluke one off LHD pair... we will never know.
In the end I plumped for a set of Bosch Aerotwin from eBay, as they came in at £23, far off the 40+ from ECP so worth waiting for delivery. Have to say, you can see the quality of the Bosch is better than that of the budget blades, so you get what pay for, but I still think £23 is expensive for two wiper blades!