There are only 400 Flt ops positions to go with reference to the announced job losses so far (13200). This 'man-power reduction' is easily covered by initiatives such as part-time, unpaid leave et al. Coupled with the fact that there are something between 600-900 retirements over the next few years it doesn't need a rocket scientist to see that BA will need to recruit.
In addition, the 744 will 'gagging' for pilots soon as the Company are keeping some a/c that they thought would go. Whether DEP or from within - pilots required!