So it seems like I have haven't bought a very good set of brakes (for choice of brake blocks I mean),seems the shimano cx70 brakes need a very specific block,all a bit crap really,maybe I,m wrong though,they are new brakes and I,ve never needed to change blocks yet.They replaced a ten year old set of avid shortys which would take any type of brake blocks practically,think I,ll go back to those.