I wont be on PPY50 for long is what i thought also but over 3 years down the line only recently have i been made full time. So view this as though it could be 5 years that's all i will say. As we know the airline business changes from month to month but i'd say it changes even more in the charter market. As the offer is 5 yrs PPY50 i would read that as a solid promise and if it happens sooner than that then that is a bonus but it certainly is not guarenteed.
Company and career wise i would rather be here than BA but others may disagree...