Hi Diane,
 
Thanks for your question. 
 
Please note that the old information regarding aches and pains and bad backs was to choose a firm mattress. The opposite is very much true these days. The recommendation is to choose a medium or soft feeling mattress as long as you have the right support from the mattress. 
 
We would need to know your body weights in order to discuss suitability of models'
 

 
Given that you disclose that you need a cool mattress this leads us to our Artisan range of mattresses as these are constructed with natural fillings and those natural fillings provide that cool sleep surface. 
 
I'd recommend having a look at our Artisan Bespoke 004, which is a true medium feeling model in those top layers providing a slight sink but not too much. 
 
I'd also recommend having a look at our Artisan Luxury, which is the softest mattress we have in those top layers. 
 

 
Please come back to us at your earliest convenience on 0161 437 4419 to discuss spring tension so we can determine the spring tension needed. 
 
Kind Regards, Lee.