I ordered them in the end and got them yesterday.
They're not that warm but are plenty warm enough for a typical UK winter. Of more importance to me was their decent level of water-proofing. Whilst not entirely waterproof, they do repel moderate rain. The bonus for me is their comfort, perfect sizing and the toe area is wide enough for people with wider feet and will accommodate thick winter socks.
One problem I was getting with my gym trainers was the windchill being felt through the mesh uppers. The Five Tens have no mesh so the effect of the winter wind is lessened.
Their grip on my Shimano MX80 flat pedals is quite something. To change foot position I have to lift my foot off the pedal. They also look pretty good and can be worn as casual shoes.