Maxwell Hall wrote:So two closed pads should do the job and a sleeping bag lining shouldn't be required?
I think sleeping bag liners are a waste of time in terms of warmth. Personally I DO use a liner (silk) but that is in order to be more comfortable (I don't like the synthetic fabric against my skin), and for keeping some of the sweat, oils and body odour out of the sleeping bag (because washing a sleeping bag is quite a task).
Some sleeping bag liners provide a little extra insulation, but nowhere near the additional warmth that some manufacturers would have you believe, and even if they did, you'd be better off just wearing more clothes instead, as they would provide more warmth than the liner, and they can be used anywhere anytime, not just when in your sleeping bag.