That's useful to know about the scratch n sniff download code maps BuzyG.
A point to note though, OS update their maps ALL the time and I would be very surprised if the digital download is also updated without incurring some sort of extra cost. The reason I say this is, at work, we have OS mapping and it is updated every couple of months to reflect new housing estates, new roads and demolished areas (amongst a whole bunch of other stuff). Naturally, as a business, we pay premium business prices for this and, if we stopped, we'd be left with the last version we had paid for.
If you think about it, OS would soon go out of business if everyone bought their maps, got the digital download and then didn't need to pay another penny for new maps because the digital maps auto-updated.