How about these two identified as saturatus:
Kennerley P 1998: Oriental Cuckoos at Tuas, Singapore on 21st October and 2nd December 1995. Oriental Bird Club Bulletin 27 55-57.
In Tring collection there is an optatus with wing length 209 labelled Singapore, number NHM 81.5.1.3291, but for some reason there is no date in my notes.
Yes I was told that Kennerley did some private ringing exercises at the reclaimed land at Tuas in the 1990s when he was based in Singapore. But I am not privy to his Oriental Cuckoo ringing records. So did his 2 ringing records nailed the ID conclusively?