I rang up yesterday.
Several times I was told no-one was available to answer, so try again later.
I eventually got through with all the usual messages such as using Qcut etc, but when I eventually spoke to someone I had no problem getting a return label sent to me.
I also tried to find an email address for CS - - there isn't one!
BTW I bought 2 sets of 2 based on their inaccurate spiel. I will certainly send one set back as it will be no good for what I planned. But I haven't decided about the other set yet, as it works OK for a light that I only need to come on occasionally for short periods.
Has anyone got any ideas what would happen if I just sent one set back?