Just noticed that Superdrug have the Gillette Mach 3 Turbo Blades pack of 4/5 for only £2.99. I say 4/5 coz the description says 4 but the picture says 5 blades.
Checked instore and the price is £8.49 so I am guessing its online only. Delivery is free over £25 or £3. Works out cheaper than almost every store even if delivery charges are included.
Hope this helps someone.