Well, I'm giving this a go now. Have had my small mat for 4 nights and while too soon to form a verdict I am prepared to believe that they may be something in this.
I sleep on it so my legs are in contact with the mat all night.
I have been busy on the PC and getting quite sore, but so far the pain has been going overnight, whereas it usually persists for days.
Pain levels rise and fall so I have to wait several weeks before deciding, but so far so good.
I'll be especially keen to see if my sleep patterns improve.