advised client send letter disputing invoice validity as they did not know where images came from, also did not profit in any way from them - and quoting DMCA 1998 Section 512 plus:

The Copyright, Designs and Patents Act 1988 (c. 48)
"97.—(1) Where in an action for infringement of copyright it is shown that at the time of the infringement the defendant did not know, and had no reason to believe, that copyright subsisted in the work to which the action relates, the plaintiff is not entitled to damages against him, but without prejudice to any other remedy."

"It is an offence under Section 40 of the Administration of Justice Act 1970 and Section 1 of the Malicious Communications Act 1988 to harass of debtors with a view to obtaining payment including the issue of letters which convey a threat or false information with intent to cause distress or anxiety."

told them to ignore them! Will wait and see.