I think County Court, eventually becoming an arrest of an A350 at Heathrow is a much more fun way to go about reclaiming the money
Cymmon - would recommend sending 2 separate letters to the address mentioned above (one of which should involve special delivery) and spelling out that you are giving seven calendars notice prior to applying to courts. It is after all the address listed at Companies House, so harder to argue with on technicalities in court.