Wing Yip (which is open to the public) sells ground almonds in 1kg bags for about £4.30, however this is for the Indian sweet-making market and is stronger tasting than usual.
http://www.wingyip.com/
Sainsburys are doing a promotion on their 200g bags of ground almonds, making them pretty affordable at 79p each.
Other than that CostCo sells bags of whole almonds, I think 1.25kg for about £6.50-£7, which I grind in a blender. This is the usual way I get my almond meal. They also do bulk bags of pecans for around the same price.
http://www.costco.co.uk/ (you can get trade membership with proof that you have a business or are self-employed, and individual private membership if you work in various industries or employers including the post office, NHS, local authorities, emergency services)
Tesco's online store shows they do big 1kg bags of almonds but I've never seen them in store - I guess it's the biggest places only.
Other than that, try your local Asian store or market - almonds are used a lot in Indian-Asian cooking, for example.
As to grinding them, almonds are easily done in a basic £20 liquidiser/blender. I prefer them with a glass jug though, as I beleive that the plastic ones might get scored. Even a hand blender will do, though that does require technique and a lot of patience.
Linseeds need to be done in a coffee grinder and I haven't got one yet. (And if you know of anywhere doing linseed at a reasonable price please share, as the mind boggles at how companies can charge so much for what is usually regarded as animal feed)
I hear that a magic bullet blender will grind coffee but they look very complated (21 pieces) and they're really not cheap.