Apologies if this post is too late to be of any practical use, but yesterday afternoon the Forest Hill Post Office at WH Smith ran out of stamps. It started with them running out of stamps for international mailings but then by mid afternoon they had used up all first and second class stamps (and presumably those of smaller denominations also). Hopefully by this morning they had got new supplies, but yesterday people were queuing for ages (three quarters of an hour in my case) only for many to be turned away when they got to one of the two tills available.
Meanwhile, stamps were still available downstairs in the shop.
The Post Office worker said they had no time to put out an announcement or put up a notice. It was particularly hard on the frail, to have to queue that long with nowhere to sit.
Also, if you’re picking up a parcel I’d advise you to check it’s not been diverted to another branch. Yesterday a man in front of me tried to pick up a parcel that he had arranged to be delivered to that branch. He’d been told it was ready for collection but it wasn’t there and the staff said they send parcels to other branches if they receive too many to store. They couldn’t tell him which branch it had gone to and told him to go away and use Track & Trace.