Use DropBox to host PDFs.
Nothing unexpected in those letters. Wait for your N180 DQ, which you can download now and fill in online.
They will discontinue before they have to pay the trial fee.
Any PPC using DCB Legal to issue their claims is not too worried about how much it costs to file a claim. The profits from the vast majority that pay up put of ignorance of the litigation process or that fail to properly respond to a claim and get a CCJ by default, by far outweighs the cost of trying it on by filling a claim.
Filing a claim is, in effect, a 'loss leader' for them. Only a tiny fraction of victims come here or over on MSE.