BA may recruit LH next year if it is struggling to attract the best candidates against Virgin when they start their recruitment.
AFAIK there is no hard rule stating BA must offer vacancies to internal bidders before external recruitment on to LH. I joined BA as a DEP on the 777 4.5 yrs ago and am still loving it, even with the current stagnation.
That said, the man one place above you on the master seniority list will always be senior to you, and initial fleet is only for 5 years, so I would definately reccommend taking the earliest fleet offered.
Good luck everybody.