I've just bought some Inov-8 x-talon 212s and so far so good, I've only done 53 miles them, including a 20 miler, I'm trying to preserve the studs on them so avoiding any road as much as possible.
My Glads have served me well and I'd happily run long stretches on road when necessary, same went for my NB RX.
a mulit terrain shoe is too much like a normal road shoe for my liking, I only wear racing flats, so a "proper" fell shoe is the best thing for me, The x-talon 212s have a bit more to them than my Glads/RX but are still nice. I was looking at getting the inov-8 roc-lite 285 as a good compromise, same midsole as the x-talon (I think) but a less studded sole. (mudclaw and mudrocs don't suit me)
Those Karrimor will probably do an ok job but I personally wouldn't get a pair, Karrimor isn't the brand it used to be, but saying that I bought a pair of Umbro Astro turf trainers from sports direct, they've got a decent studded sole and were only £12 marginally more cushioning than my Glads and I have run 23 miles in them, don't know where they are now tho.