Pushing the envelop - Differential Pricing - Office Dog / Post Office

[Adrian Essex]

I just bought a pack of Post Office branded envelopes in Office Dog for 80 pence - I chose OD to avoid the PO queues. When I did join the PO queue to post one of the envelopes I discovered the PO price for the same pack is £1.49. 

I don't think this represents an arbitrage opportunity.