Having seen a skip-lorry reversing into the lane this morning, I assume he might have been told to move because his van was blocking access to the yard.

Given Network Rail's lack of interest in the condition of the subway, despite it having been brought to their attention many times over the years, it wouldn't surprise me if NR had been oblivious to the fish van parking there until now. Hopefully once the work in the yard has finished they'll sink back into their usual state of disinterest and normal service of Thursday morning fish-selling can resume.