I think that Instagram account is mistaken. I did find a Margaret Monypenny who was the partner of an Alexander Ogilvy, son of a James Ogilvy, but this Alexander was born before 1548!Accordin to the ollowing Instagram account, Alexander Ogilvy has a girlfriend/partner - her name is Margaret Monypenny:
He has an Instagram account (I didn't try to check if private or not) and he appears sometime on photos which his sister puts on hers one.Alexander Ogilvy seems to keep a low profile and out of the media spotlight.
I believe 28 is actually the maximum age to join the British Army as a regular officer.That's quite a change from graduating in Computer Science and Economics and a subsequent job in a tech firm in the States to returning to the UK to start Sandhurst at the age of 28 - with the intention to join the military I suppose.