So, after numerous spam emails, Communicado Ltd have said they won't pay damages and that I will lose any claim I make.
Interestingly, their last email seems to have given up the pretence that it's legal, but that it will be thrown out as my claim amount (a paltry £10 per email) is not justifiable.
I've finally been able to file the claim which has now been accepted by the court system, and Communicado Ltd will be served in the next few days with the vital words "Do not ignore this claim form. If you do nothing, judgment may be entered against you without further notice."
They will have 14 days to settle or they will end up in (my local) court with all the evidence against them.
Roll on the 14th of September.