Thanks. By cup, i mean cap i suppose. On the left crank there is a threaded aluminium cap, which you tighten in order to push the crank onto the spindle. When the crank came loose/off you could tell it was loosening by the movement, but also you could see it coming away from the edge of the bb, with the spindle being exposed. Currently the 'cap' is tight, there is not gap between the bb and crank, yet there is play. I'm not with by bike atm, but will double check that it isnt still the cap issue, and is definitely the bb i suppose.