British airline Thomas Cook Airlines based on Manchester are offering some great solution from UK to various destinations in Cuba. Consider their charter service to fly either from Manchester or London to Cayo Coco or Holguin already for £309! This is price for a round trip flight including all taxes and fees. Hand bag (6kgs) and checked luggage (20kgs) are included as well. 
You may find the lowest fares mainly within April and May (Manchester) or in October 2016 (London). Very limited travel options are available in said travel period. The fastest way to check the cheapest travel dates is directly with Thomas Cook here. They are offering month´s view (use "Low fare finder") so you can easily find out if there is any good option for you..
Booking samples
Booking sample of cheap return flights from UK to Cuba from £309 here. In this case you would fly from Manchester to Cayo Coco on 20th of May. You would return to Europe from this exotic Caribbean isle on 27th of May 2016..
