Zanussi FJS1397 - Leaking from front?

While on a standard cycle I noticed wet carpet tiles at the front of the machine. I checked all external pipe connections, which were fine and then watched another wash cycle. No water leaked during the initial fill of the machine although soapy water started to leak from the front during drum rotation. Initially I thought it may be a door seal but initial inspection showed nothing. I then removed the back of the machine and checked all pipes and hoses and found nothing obvious. On running the rinse program there was no leak, but the water level in the empty machine was low. I stopped the cycle and started to intermittently fill the drum via a hosepipe through the open door whilst checking for drips with a torch from the exposed rear of the machine. After a short while I noticed a series of drips from the very front of the drum but feeling with my hand, as I could not get to the front of the machine without major disassembly, it was evident the water was not from any hoses but seemed to be coming from the front of the very bottom of the drum where the front ballast/blocks are attached. For confirmation the water in the drum was well below door level which rules out the door seal. Any clues where the water is leaking from?... or whether I need to assume that the drum itself is damaged (which I would have thought to be unlikely). Any help appreciated.