Good Afternoon Mark,
 
Thanks for your question. 
 
With the information you disclose we always advise side sleepers to avoid anything that's too firm in the top upholstery. This is because a firm mattress for a side sleeper will cause pressure point pains in places such as shoulders, hips and knees; Not ideal. 
 
As such we'd always advise to go for something either medium or soft in those top layers. 
 
At your body weight you're matched with ourselves with a Medium spring tension to get the right level of support. Once this is established you can effectively ignore it and concentrate on those top layers. 
 

 
I'd advise to have a look at either our Origins Pocket 1500, Artisan Naturals or Artisan Bespoke 004. 
 
The Origins Pocket 1500 is a pocket sprung mattress with synthetic fibres. The Artisan models are pocket sprung mattresses but constructed with natural fillings; The Naturals has 85% natural fillings whereas the Bespoke 004 has 100% natural fillings. 
 
We would guide anyone to the Artisan range if there are heat issues during sleep. This is because natural fillings provide a much cooler sleep surface. If there are no issues with this then simply stick with the Origins range. It's worth noting that the base the mattress goes on top of can make a difference to the feel. A solid top platform base will always firm up the feel slightly. A sprung base will always soften down the feel. Slats of any variety will always give the mattress a firmer feel. It's worth factoring this in to your decision; It won't make it feel like a completely different model but it does contribute. 
 

 
I hope this has answered your questions fully but if you do have any further queries please don't hesitate to contact our office on 0161 437 4419.
 
Kind Regards, Lee.