Which bed to purchase

We have had a Millbrook double bed for 10 years. Having a comfortable bed was a revelation to us. We both have bad backs and never had a bad nights sleep in this bed. We now want to change to a 6'3" bed where two singles zip together, but replicate the things we like about our current bed. We don't know what firmness we want, but suspect medium. We want excellent pocket springing with pocket sprung base, a latex layer and a turnable and rotatable mattress. We can't find this combination on your website. What bed do we need?