I found the Greentrax albums and four other Isla St Clair recordings listed at Folk On Line Directory of Events and Recording Order Listings ("Fol-de-rol")
St Clare, Isla. 1979. Isla.. Decca, LP SKL 5317.

St Clare, Isla. 1981. sings Traditional Scottish Songs.. Tangent, LP LP TGS 112.

St Clare, Isla. 1981. The Song And The Story.. Clare, LP ISLA 1.

St Clare, Isla. 1993. Inheritance. Moidart, MOICD 008.