Britannia's sponsorship states you must pay £15000 of the cost, and be a Britannia employee for 3 years afterwards, or pay back the rest of the training costs pro-rata. So they're simply giving £35000 (prob. less after tax dodges or bulk deals....) to Bae Jerez, and for that they get to hand pick a top-notch pilot to mould and use for the next 3 years. Suddenly doesn't look too bad an idea, as opposed to recruiting, say, a 1000 hours guy who they don't really know the training history of, and could leave at any point. That £35000 could easily be lost in the extra salary or type-ratings the experienced guy could rightly demand over the 3 years.
doesn't mean to say I'd do it myself, but its the best reasoning I can come up with!