'Yes Wild Mountain Thyme was written by William McPeake in 1957.'

I thought old Francie McPeake wrote it but checking on the 1962 EFDS Publication FOLK, he's quoted as telling Peter Kennedy -
"I heard an old uncle of mine sing this - years and years ago. (They were really a kind of cattle dealers up in the County of Monaghan - he really belonged Dungannon). He'd got a good many old songs like that and I used to hear that one many times. It was a thing from my boyhood days - I always liked and I started to work it on my pipes." Frank McPeake, Belfast, July 1952.

OK, so who is right? Guest I Don't Know or Peter Kennedy/Frank McPeake.
Just wondering.
Robyn