I wish I had never booked with Carlton. Don't be fooled by their request for an admin fee when Carlton cannot provide what you booked. Carlton tried to charge me £75 admin fee for a refund of flight costs (when coronavirus hit and flights were cancelled) and they said it would take months to pay me. I refused to pay the £75 and instead requested a 100% refund from my credit card company under Section 75 of the Consumer Credit Act. I received the 100% refund from my credit card company, with no admin fee at all, really quickly (in about 3 weeks). So claim the refund from your credit card company where applicable. It is free and much quicker and easier.