In reply to Big jack o:
One thing I look at very carefully when managing groups outdoors and when working with clients with reduced mobilty, is the reduction in body heat generated.
Clothing and layers are usually only insulators, not actually heaters. If you get into them cold, or your temperature lowers despite them, then no amount of layers (regardless of what they are made of) will warm you up again.
Have you considered heat packs? You can get reusable ones that need gentle handling but are pretty good. I vaguely remember a North Face jacket that had battery powered heat pads in it, but I guess it was rubbish or ridiculously expensive since I haven't seen any other examples of this since!
Another consideration could be how much heat you are losing though your legs. If you aren't using them (walking) and your heart rate is low as you are sitting on the scooter then you could be losing a lot of heat through the tops of your thighs - maybe consider extra warm trousers or thermal leggings?
Finally, I agree with deepsoup - Cotton is pretty poor as an insulator if it gets at all damp. Merino Wool baselayer products are good, though pricey.
Hope you find a good solution.
J
