How much flexibility to change date is there on a T class
A question for the experts. How much flexibility is there in a J/T Dom/TATL WT+ class booking. I have a BA Hol (Flight+car) booking departing in 4 weeks time but may have to change it - ideally I would like to do the same trip but in June next year. Is it possible to change dates and how much does it cost? How late can I leave it before making the change? Ticket was original booked in August.
Many thanks.