Originally Posted by flarmip

They don't appear to be a member of any ADR scheme. You can use the CAA PACT (Passenger Advice and Complaints Team) procedure, but I would imagine this is likely to be a very slow process as they are likely busy (like most regulators).

The alternative would be to bring a claim in the UK courts. That being said, doing so against a foreign-domiciled carrier (without a UK office) is always going to be a rather frustrating exercise as you'll have to jump through hoops to effect service on them.