In reply to digby:
> Must be bigger than Musselburgh Aldi - 146 allowed in!
I have no idea about the Aldi in Musselburgh. But the exhibition space in the NLS is small, and bear in mind that this is busy tourist season so there'll be plenty of potential walk-ups.
I am not defending the protocols (if any) in shops. But having to book in advance for this exhibition makes sense to me.