Origins Pocket 1500 or 2000?

Hi guys,
For the last year we've been sleeping on a Silentnight Seoul mattress ("Mira"coil and Memory Foam) which we got for a bargain price. We find it quite uneven, and my wife complains that she can feel the coil pushing through the foam layer into her back.
We tested a few Silentnight mattresses recently which we hoped to replace the Seoul with and found that the Silentnight Ashridge (1400 pocket springs with memory foam layer) to be most comfortable to my wife's preference. We both weigh about 10 stones, would the Origins 1500 be similar to the Ashridge? We are looking for a firm feeling mattress.