its already £799 with TUI seat only at the end of Jan next year per person shoe boxed in to a 787. I can see more long trips dahn sarf this year.
There is more space on a TUI Airways 787 than a BA 777 refurbished or not. Plus the service onboard is practically similar with complimentary drinks, meals and IFE.
That said, it is usually cheaper to book a package holiday with them than flight only as this is their target market being the airline for a tour operator.