Such things *are* handy, Ian, especially in the absence of a cake 'n' coffee shop!
I find when touring, I can stand mornings down to about 3°C so long as I'm riding and working hard (and it is dry) if I wear a long-sleeve knit jersey, wind jacket and 3/4 tights atop my cycling shorts. When I stop, I chill quickly, so I usually grab something to put on. A light fleece often does the trick, or my wool longsleeve jersey with wind panels in the front.
Recently, I picked up a cheap (USD$5 on closeout in a tub at the pharmacy, of all places!) synthetic-filled "puffer" jacket from China that crams into a small stuff sack. It is black (as are all my cold-weather clothes; it makes a difference in milking that little bit of extra heat from a watery sun) and highly calendered (shiny) and breaks wind well. The bit of insulation (not much different from a NorthFace ThermoBall jacket) seems to be doing the job for such short stops. I think I'll keep it tucked in my rack pack for rides well into late Fall.
My problem seems to be finding some good winter tights now my old woolies-under-lycra combo is succumbing to age. I've sent for a pair of wool tights from an eBay seller, hoping they will fill my needs. We'll see; they're due to arrive next week. If I can occasionally pair them with a lycra over-tight to break the wind, I may once again have a winner.
That Rab jacket looks *nice*, Ian.
All the best,
Dan.