In reply to frqnt:
How much do they cost?
I managed to buy a Thermarest Prolite Small for 40 pounds from Cotswold few months ago. It is exactly the same size (including the thickness), but tougher (50D/75D vs 33D/33D) and lighter (320g vs 400g). R-values are 2.2 vs 2.5 (the latter is estimated).
They still have another model left, which is 91cm long:
http://www.cotswoldoutdoor.com/therm-a-rest-prolite-x-small-mattress-with-s... . It weights 230g... If you aren't too long, it might be worth considering.
P.s. I just mean... If you are afraid of getting Alpkit mat broken/faulty, Thermarest can be an option. I haven't heard many negative reviews about these products.
Post edited at 14:03