You're just in luck, I have a B9 version, 13k in and iv'e just literately changed my blades an hour ago. Was going to get original parts (OEM) at £40 but went for Bosch via amazon link to them:
Amazon product
cost £20. Deliver took 4 days. Slight difference in the design as the oem has a metal strip with two metel ties where as the Bosch are all plastic, they look better then the OEM and easy to fit, you don't have to put your blades in to service mode to get them off and replace them. Its a 1 minute job. BOSCH Aerotwin A298 s