Yes Jackonicko, you're quite correct... the risk is indeed "unquantifiable".
How then do you suggest that the individual who underwrites that risk, ie ACAS, decides whether that risk is acceptable (or not) and that the ac merits a RTS?
Do you not accept that an accident where the cause is not positively determined, would have every man and his dog wanting somebody's head on a plate as "the ac were unsafe....BD said so years ago."
The ac can indeed be flown, however it was decided that introducing the 8 ac for an expected 40yrs required the problems to be addressed, hence 'Fix to Field'.
Hopefully, there should be more news in the New Year , and then everyone can start having a go at the programme schedule- You've got to think there are too many wannabe DPA employees on this forum judging from the comments above!