Went out and bought the  "Campri" bottoms from "Sport Direct" today,to go with the top, £7.99 reduced from £22.99, not so much for cycling but for work these cold nights, but unlike the top (in reality I may not have gave the top justice as according to my clothing worn/temperature chart, it was the coldest day that I had been out this winter) I was very impressed how warm they are, not just standing around at work but when I cycled to work last night and returned this morning, temp -6.5 it was very noticeable how warm they were.
The material is very thin like the top and ideal to wear under tights etc for an extra layer if need be. Because the material is so thin as well, it should be possible to wear two pairs at the same time, tops as well.