Helping to choose a double mattress

We are a married couple aged 71 and 66. We weigh just over and just under 9 stone respectively. Just realised our mattress Myers Vancouver Pine is 16 years old. I have had some back ache recently so feel we must change mattress but find choice bewildering and are not certain about memory foam. Do not like to be too hot in bed. We have a slatted bed base. As we are both small and getting older we do need to be able to lift the mattress to rotate it occasionally and will need handles please! Have been looking at a Rest Assured Cassis Natural 1400 but would appreciate some advice.