Did John Caird marry a Princess? Still looking

Biography
John Caird, an Edinburgh surgeon, died in i861 aged 74.
Age is consistent through 1851 and 1861 but in 1841 is aged 58.
Calculated birth year based on 1841 is 1782/83 (born in Kirkinner WIG)
Possible? - IGI extract for a baptism at Kirkinner on 5th September 1781 to same parents given on death certificate.
Married Charlotte Averne in Isle of Man in 1803
(I think it was Annie who first reported this - IOM. My first thought was Isle of Madascar

Thst's in the Indian Ocean, isn't it. Ah well

)
So he was married (1803) at the age of 21 say.
Admitted as FRCS Edinburgh - per Tidy 1811
Promoted to FRCS Examiner - per Tidy 1822 (Must be good)
Signed a Surgeon Certificate in Edinhurgh 1826 - per Shaun.
In 1826 he would be 45.
What about Charlotte?
She was with John in Edinhutgh - he a Surgeon - aged 57. Not born in Scotland but a E in the last colums. Would that cover Isle of Man in the enumerator's instructions. She died in 1860 at 27, Montague Street and was buried in Grange Cemetery. I assume that is/was in Edinburgh. Are there transcriptions available?
I have no idea whether John and Charlotte had any children. I wondered whether a memorial inscription or an obituary for either of them may provide information.
Where is the best place to look, please?
Now an oddity.
Charlotte died in 1860 at 27, Montague Street. On the DC John Caird, surgeon, is her husband.
However both in the 1851 Census and the 1861 Census Charlotte is not there with John and an Elizabeth is shown as John's wife

Annie, after all this time, I have emailed the Royal College of Surgeons seeking information on John Caird. Obviously I'll post the result.
Regards and many thanks
Reiver