Mary/Sue,
I have not been following your string but just spotted reference to "Booilevelt".
It has been a long time since I first cycled down in that area and memory fades,
however, it is off what is now the A15 road, South East of The Hibernian and almost due North of the Cornaa tram stop
J.J.Kneen tells us in 1926:-
1703 Man. Roll Boalyvelt
1734 Dioc. Reg. Ballavailt
1858 Man. Roll Boalleyvelt
1867 Wood Booleyvelt

Mx. Bwoallee yn vuilt, 'fold of the wether'

My OS 1869/1870 large scale map shows:- Booilevelt
The/my OS 1"" map of 1955 shows:- Booilyvelt
I.O.M. Public Rights of Way (1:25 000) map of 1983 shows:- Booilyvelt
Landranger OS since metrication shows:- Ballavelt (mine is 1984)
All aprox. grid ref. SC468907

Leslie Quilliam did not seem to refer to it in his writings.
nor does Phil Kelly in his lists of Placenames c1993.

"Charles Kerruish-A political Biography" by Derek Winterbottom (2002) page 2.
this refers to his Kerruish ancestors, by the early eighteenth century, being associated with four neighbouring farms, Ballellin,Ballafayle, Booilevelt and Cardle.
Patron of the I.O.M.F.H.S. (Mrs Anne Craine) is his daughter and could be of help.

"Curragh"
I have witnessed many boggy areas in Andreas, Jurby, Lezayre and even Ballaugh drying up since the nineteen fifties.
All decent maps show small boggy/marshy patches scattered in Kirk Maughold Parish
but I do not know of a Maughold Curragh:-
However "A History of Kirk Maughold" (which you both may have) refers to the "Curragh Road" on page 200.
Peter.