I’ve got one of those tiny Am-Tech mini-mattocks, it’s a surprisingly handy wee thing- but you need to put in a lot of energy if you want to get much done, the tool doesn’t do any work for you like a proper mattock does. Might take the pick end off it for easier carriage.
Folding shovels… I think they’re mostly the same, “army surplus” or “nato issue” is pretty meaningless.
Anyway, this one:
http://www.ebay.co.uk/itm/Folding-army-spade-shovel-/321091631805?pt=UK_Collectables_Militaria_LE&hash=item4ac28d7abd
is alright. Bit too short, and the blade’s too pointy and flat, reshaped mine a wee bit. Durable enough for most work, don’t try and use it for serious hacking though. I’d get another, but I’d go for a soft bag one, this plastic box thing is too bulky.