Not that there will be ANY DEP recruitment onto the 777 for a long time!
What makes you so sure? Those who are 'unfrozen' and bidding have gone to either the 744 or the 777. Those remaining are frozen and can only bid aspirationally or want to enjoy their position within their fleets. The 744 training pipeline is so clogged that they have just about had to admit that they can't achieve all training and conversion this financial year.
Two more 777-300's to come and there is flexibility on the 777 fleet to pick up the lines that the 744 can't achieve plus the possible expansion of LH leisure routes from LGW.
BA recruited DEP onto the 777 at the end of the last phase and there is no reason they couldn't do the same now if the demand/demographics required it. DEP 777 would be a long lonely place at the bottom of the list mind you!
Remember, it's BA we are talking about, reactive not pro active and never say never!