Unless one of the "British" garlands tells a longer story than that I've been able to see by going to the Bodleian site, no British version that I know of has the "heathen" episode reported by Laws. There are several Silk Merchnats Daughters in the Madden collection but my surmise is that they, being most likely nineteenth century printings, also lack this feature.

No English, Irish or Scottish traditional version that I have seen has this aspect either:

Recordings Tom Lenihan (Paddy's Panacea - Topic 12TS363), Walter Pardon (Our Side the Baulk - Leader LED2111)

Notations Stubbs and Richards : The English Folksinger Ord: Bothy Songs and Ballads Greig Duncan Collection vol 1 HED Hammond collected a version in Dorset which is in Frank Purslow's - Constant Lovers There are also several in Cecil Sharp's Collection (ed Karpeles) but I haven't seen them.

It seems the heathens are a feature mainly of the versions which were found in America. Not having seen older sets from Britain or Ireland I can't say whether this is a retention or an accrual. But whichever it is it speaks of differing conditions which led to the difference.