Quite like my dhb thermal tights and would recommend those but I'm starting to feel the cold more nowadays.
Were the decathlon ones the equivalent of these? http://www.decathlon.co.uk/aerofit-700-thermal-cycling-tights-id_8343189.html
When you say winter, what do you want, something for the real cold days or something 2-10 deg say?
If the former you want windproof ones. The decathlon ones I have are windproof and were about £50. They also did Roubaix type for a bit less. It was a couple of years ago though so not sure what they have now.
Were the decathlon ones the equivalent of these? http://www.decathlon.co.uk/aerofit-700-thermal-cycling-tights-id_8343189.html