From speaking with friends and initial training colleagues there seems to be something of a lottery to the whole business.
Every company has its recruitment policies and filters which, understandably, are kept very much to a need to know basis and so I would say that it is unfair to say that there is absolutely no process. Notwithstanding this, however, I have been told by a friend (older and maybe wiser) that in their past experience the recruitment of low-hours pilots involved a notice board, some beers, a group of captains, some CVs and a set of pub-arrows!
Setting speculation aside I can only attest to two observations:
1. There is a high chance of OAA grads getting a call within weeks i.e. 8 - 10 weeks, of final flight
2. That chance seems to diminsh with increasing proximity to, and after crossing, a well known wall in Northumberland and other northern English counties, but absolutely does not disappear altogether.
That is just, JUST, an observation.