Just an update to this thread.
I sent a complaint in by email on the same day as this thread started. Heard nothing for 3 weeks so I sent another email reminding them and had a response on 7th June telling me that my complaint had been logged on 14/5 and asking me to wait 30 days from that date for a response. Never had one so I reminded them on 26/6 asking what the second stage of their complaints procedure was. Still haven’t heard from them so I sent another one today and copied it in to their CEO. I’m not going to just let this drop.