I'm not talking about the after dinner entertainment at Bristol, but Focus DIY have Nitromores for £3.49 for a 1 litre tin - this is half price. A 5 litre tin is £27 and a 500ml tin is £3.59, so either this is a very good offer or Focus have mispriced.
I've checked and this offer is on at all their stores (except Saltash which I cleaned out).