By the sounds of it, with the change of heart theyappear to have had regarding relocation, it's going to need folks outside the marylebone/aylesbury area to play a blinder at interview to stand any chance at all.
It does bring into focus the much discussed topic of relocation - yes there are risks employing a candidate who has to move, but uprooting does show an enhanced level of commitment and surely chiltern just want the best wherever they're from.
Finally regarding the two sets of interviews weeks apart. Yes, as mentioned above, probably "batches" was the wrong word, but undoubtedly after the first set the guys would have had a "wash-up" of all candidates and pools of 'possibles and probables' formed. This is where being in the second set of interviews will help as any positive impressions given will be fresher in the interviewers mind at the final wash-up.