looking to replace Silentnight mattress with soft layers

Hi, I am looking to replace an old double Silentnight mattress. I am 5ft 1" and weigh 10st 13lbs. I am a side sleeper and sleep on my own. I like quite firm support underneath but quite like a softer layer to lie on. At present I have a mattress topper to give some softness to the top of the mattress. I like the bounce of pocket springs as I have tried lying on memory foam and found it more difficult to turn over. I have a sprung divan base that the mattress sits on.
Please could you give me what you think would be suitable options ranging from mid to more expensive mattresses.
Many thanks
Pauline