Which mattress would be best for us Artisan Pocket or Bespoke 004

We want to purchase a new mattress for our wooden bed frame (double - not enough room for anything bigger!). My partner is about 14/15 stone and had a spinal fusion operation in the lower back some 10 years ago but his back problems are ongoing, his neck and shoulders are now affected. He was comfortable with his very old Hypnos mattress which was very firm, but I found it too firm. I am about 11 stone, curvy for want of a better word! and also suffer with arthritic pelvis and knees after a horse riding accident (what a pair!). We are struggling with the mattress that we have on the bed frame at present it seems very 'boaty' and is rubbish really. We were recommended to try yourselves by someone who had purchased one of your mattresses. Please could you advise us on a mattress you think would be suitable with our two problems. I have looked at the Artisan Pocket and Bespoke 004. He says he likes/needs firm, supportive, and hates memory foam (too hot), I really don't know what I like, but definitely don't like a firm Hypnos! I have tried toppers but didn't like memory foam either. Although it is probably not a lot in the mattress world, we could spend £1500. A decent night's sleep would be good, is it possible for that price? Thank you.