The OAT thing is a foundation degree in Air transport studies. There is no extra cost on top of the normal APP course....so in essence you pays your cash and you gets the fATPL course as normal as well as a foundation degree from Buckingham Chilterns uni. This can be upgraded to an honours degree or indeed a masters degree at a later date through distance learning. This becomes a standard part (non optional) from the September courses I believe. Most of the coursework required to obtain this I think is obtained through having done the ATPL theory exams, but you will need to do a couple of other papers.
This is all hearsay to some degree, although having just started at OAT, it is at least a fairly decent representation of my understanding of what has been explained to us.
I would suggest that the best place to get the full picture would be to give OAT a bell and speak to one of the training advisors who will be able to answer more fully.
Hope that helps a bit.