We have just been to this and it was extremely good. However if you have booked tickets, make sure you print them as they don't have scanners which read the booking on your phone. You have to join a queue to have them printed!. We were told NOT to arrive early and so, by the time we had queued up and got the tickets printed we were about 30 minutes late for our time slot! Had we known about this in advance it would have been very helpful. Very few were turning up with printed tickets.
We went to this in Manchester. We didn't have to book a timeslot or need a ticket, we just turned up. Had to queue for about ten to fifteen minutes. It must vary with the different venues. Lovely exhibition but he must have hell to live with!