I decided today to replace a couple of ten-years-old OS Explorer maps, because I had found the hard way that one didn't show a new junction on a trunk road, with slip roads, service area and motel where I wanted to walk, while on the other map a car park I wanted to use as the start of a walk had been closed some time ago.
Looking around the Net at map prices, I was pleasantly surprised to discover that Ordnance Survey are giving 30% discount if you buy 2 or more maps from them online. For 1:25,000 Explorer maps, that works out at £5.59 each instead of their usual price of £7.99, and there's no carriage/handling charge.
The offer is only until 29 Feb. It seems too good to be true, and I do wonder if maybe OS are bringing out later editions, and getting rid of their old stock? Meanwhile, I've taken advantage of the offer and I've just ordered replacements for two further ones as well.