Forget the eTrex 10 if you’re after a mapping GPS as all it is is a capable old skool gps. Their eTrex 20 and 30 however are the ones to ask Santa about. It’s not just that they’re priced at £180 and £230 respectively which is much cheaper than competing fully blown mapping gps, but they offer much more. They’re light, at 142g. The battery life is impressive at 25 hours and with the top of the range eTrex 30 you can even transfer your GPS data wirelessly to others with similar devices.
Garmin have brought out a £20 OS mapping licence – called BirdsEye Select Great Britain – though I promise that it has nothing to do with fish fingers. For this, you get access to 600km² of of 1:25,000 mapping, and if you’re lucky you may get bundled with your device. That may sound like a lot , but if you consider that an OS Explorer map can have over 400km² on one side (my Anglesey East map has 460km on one side – it was just the nearest map to hand). So you’re not going to get your full national park on one of these and you’ll be limited for a long trip, but probably more than enough for your usual day walk or walking holiday.
You can supplement this with 1:50k mapping, but the Wales section comes complete with the useless addition of southern England (and if the maps you need are southern England, then likewise they come with the useless addition of Welsh maps!). However, for just shy of £80 you can buy the 1:50k coverage for the UK National parks, including most of the more interesting hilly areas (though for Wales you miss out on the Cambrian and Berwyn areas as they aren’t protected), which makes it a much more appealing package. Even if you buy the £199.99 complete UK coverage, then the cost compares favourably with the Satmap.
The downside to this is that the devices are as hard to find as lunch spot on Snowdon in July, though they have now started to appear as available in most online outlets.