Therm-A-Rest Womens NeoAir XLite Ultralight Three-season Sleepmat  £166.50

I upgraded a tiny non-insulated camping mat to this slightly larger mat and the benefits have outweighed the additional bulk and weight. That said this is still a small and light mat! The dimensions work really well as a 5ft 8" female side sleeper. When wild camping I was aware of the rustle as I inflated the mat but otherwise it wasn't as noisy as I'd expected at all. Very warm and comfy. It'd definitely recommend it!

First the good news: this mat is super-lightweight, comfy and nice and warm. I got no sense of the noisiness other reviewers have complained of; maybe Thermarest has sound-proofed it in recent times. I would advise anyone to purchase the separate pump. It's very quiet and so tiny and light that it makes no diff to your load. The pump sack that comes with the mat is a lot of work. It's great to pitch your tent, get the pump going, and then tend to cooking your dinner while the pump does the work.
The less good news may only be relevant to a minority of campers. I am a restless side sleeper and like to sprawl in all direction sand postures. While I am small (5'3", and weight 114), I wish I had purchased a wider mat. If you sleep neatly on your back, or stay on one side or the other and don't sprawl too much, this mat would be perfect. More width would of course add slightly to the weight of your pack, but in my own case it would be worth it.