The entire six-part 2014 radio adaption of Good Omens, with Mark Heap as Aziraphale and Peter Serafinowicz as Crowley, will be broadcast on Radio 4 Extra at six in the evening, Monday to Friday, and available on BBC Radio iPlayer for 29 days afterwards. If you can’t access iPlayer where you live or don’t manage to listen before it goes off iPlayer, another user has linked the series here.
Also features Simon Jones (I’m assuming the one who is known for playing Arthur Dent) as Mr Young, Josie Lawrence as Agnes Nutter (who plays the same role in the TV adaption) and Terry Pratchett and Neil Gaiman as police officers.