Hi Tracey
From IGI, siblings showing to your Robert including his entry:
1. JOHN BOAG Birth: 25 MAR 1819/ Christening: 27 MAR 1819 Forteviot, Perth, Scotland
2. ROBERT BOAG Birth: 19 JUN 1814/ Christening: 26 JUN 1814 Forteviot, Perth, Scotland
3. CATHARINE BOIG Christening: 20 APR 1806 Forteviot, Perth, Scotland
4. MARGRET BOAG Christening: 22 JUL 1810 Forteviot, Perth, Scotland
There are 3 marriages showing for a James and Isabella. This one looks more likely given the birth years of the children above:
JAMES BOGG Marriages: Spouse: ISABEL MUNROW
Marriage: 11 DEC 1805 Forgandenny, Perth, Scotland
Regards.
Monica