Forguette, thank you. Interesting! And enlightening. Turns out that "William Scrougie, Roddin" was the Minister of Rathven at the time, becoming the Bishop of Argyll.
Here's a bit from the Fasti: "WILLIAM SCROGIE, M.A.; pres. by George Hay of Rannes before 7th March, and ord. 18th April 1649; app. Bishop of Argyll (q.v.) but retained his parochial charge till Lammas 1667." - Fasti.
Cramond has lots on him in his book The Church and Churchyard of Rathven. I cannot see anything which would identify Roddin as such but there's a reference to "the Bigging on the Mans of Rathwen, at Mr Wm Scrogie's entire in anno 1649". Maybe someone can translate this! Earlier "...the whol begging on the mans..." Is Bigging a place or just a way of saying 'making bigger'? Is Mans, Mains or Manse? The context suggests Manse of course.
I don't suppose for a minute the current Manse is on the site of this 1649 Manse, maybe someone will know. But Roddin appears to be the name of the manse in Rathven and/or its associated glebe, and must be basically in the middle of the village close by the old church.
So back to my question: where was "in the Rodin"? (And happily I have found the reference in the now-online Rathven Kirk Session - must have missed it when wading through the actual book in Edinburgh years ago.) The above indicates it being in the middle of Rathven village. Although then I have to ask why the OPR records the parents were in Arradoul when child was baptised (20 Dec 1732), yet the Kirk Session records them 'in Rodin' and 'in the Rodin' (14 May 1732). Maybe I've answered my own question - the couple moved in the summer of 1732. Or: would the Minister live 'out of town'?
Forguette, your persistence has paid off! I've got a lot more background to chew over.
Thanks.