I suspect what we'll see is "one person per unit of seating" (i.e. row or bay of 4) plus masks. Even if masks aren't that effective, they could be used psychologically to "justify" a climbdown from the 2m in some circumstances, as I'd probably say the vast majority of the public think they might have at least some effect.
Indeed. It's only natural that the Government would want to point to something actially happening elsewhere to justify such a change in policy. It makes sense in that way.