After a fruitless visit to Halfords yesterday, I was looking at ordering the Bosch N70 from wiperblades.co.uk for £11.01 plus £3.25 postage ... but they also offer a Bosch retrofit Aerotwin AR70N for £9.71 plus £3.25 postage. Just need to check the fitting dimensions as advertised.
"The Bosch Retrofit Aerotwin AR70N is compatible with the hooked wiper arm: Type H15 - 9x4mm (hooked), Type 230 - 12x4mm (hooked) and Type U4 - 16,2mm (L) & 16,4mm (K)."