They never did email any instructions, but via the chat on the ticket site, for anyone else chosen for collection:
Tickets are to be collected from 12:00 at window 6 in the matchday ticket office, located to the left of the main reception. Only a limited number of ticket holders have been...
‘Arrived’ today. At least ONE of them did. Mine is marked on the receipt as ‘COLLECT’.
Would be nice if they actually included (or emailed) some details of that.