I bought a 1000 pocket spring mattress from this company last week. They had quite a few in that category (http://www.mattresstime.co.uk/pocket-sprung/1000-pocket-springs) and I wasn't sure which one to order so contacted their live support who actually recommended I buy the cheapest one, which I didn't expect. But found it refreshing as it showed they had listed to what I actually needed.
It arrived just 24 hours later, and it is really comfortable! If you haven't tried pocket springs before I recommend you do, and at the price of £109.00 without delivery charges these mattresses really are a steal.