Amazon: I had a look this afternoon.
There was a Costa employee round the back who informed me the rubbish was residential from the flats above the shops. This rubbish had been initially deposited in the bins used by Costa, but since Costa are subject to fines if they handle residential waste, the rubbish was removed from the commercial bins and left on the roadside. I mentioned this was of some concern and complaints had been made. She seemed to think the road was 'private' and owned by the Co-op.
I checked this out with Co-op's deputy manager who assured me the road was not owned by the Co-op. I showed him the "Costa" rubbish and also a second pile at near the back of the Co-op Chemist on the walk-through paving near the car park.
I then popped into the library for 45 mins and on my way back I noticed the rubbish at the back of Costa had been cleared! Disappointingly, the 2nd pile halfway down the road is still there. I don't know who cleared the waste.