Therm-a-Rest (Cascade Designs, Inc.) - Saros 20F/-6C

It's probably worth pointing something out here: a lot of people, when they see "military gear", they assume it's the best quality. The reality is that military gear tends to be be manufactured for the cheapest price possible, because it has to be made in such large qualities. As such, while the gear is attractively priced, you're not necessarily getting the best performance, or even value for money. For example, the Elite 5 is rated to -15ºC, and weighs 2.4kg, which is really heavy. By comparison, the [Thermarest Saros 20 Synthetic Sleeping Bag](https://ultralightoutdoorgear.co.uk/saros-20-synthetic-sleeping-bag/) is rated similarly at -9ºC (more than enough for most camping in the UK), and weighs only 1.5kg, for roughly the same price. And yes, you should always be using an insulated mat under your sleeping bag. Their temperature rating assumes this to be the case, so removing the mat removes some of the bag's thermal rating at the same time.