Type of mattress and base

Hi I'm looking for a double mattress. For myself. I live alone. Female. 59, 5 foot 7 in..about 13 stone. I have slightly wider than average shoulders. Side sleeper, wake through the night and turn over. I do get hot feet. I do not want a too firm bed, ie lying on top like a board. My current mattress is 7 years old. It is a 'healthopaedic' smartness 3000 climate. With air suspension pockets, 3000 coils. memory foam topper with thermoregulation fabric ( cellulose paraffin cells). it is no turn. My current Base has sprung slats.
I was after a bed for spare room, but thought perhaps I could buy new for myself and put existing bed in spare room.
I don't mind paying extra for comfort. Can you advise please, especially on mattress but also on new Base with drawers.
Many thanks
Denise Greenwell