Hi Lorraine,
In Tom Corteen's burial transcripts he has:
Robert GARRETT 53 yrs. [residence] Ramsey buried Maughold 8 Feb 1903.
And Isabella GARRETT 58 yrs. [residence] Ramsey buried Maughold 8 Jan 1911.
So, sorry, that doesn't help with your marker. If you are a member of the IOMFHS you could write to them and ask whether they can help with this?
Sue