Hi Kim - thanks for trying! It's a really tough one this and has always stumped me. It stems from a great family tale.
I'm pretty sure that the Margaret buried in Old Dalbeth is not my Margaret as I can't see why she would be buried so far away. She lived in Dalmellington in 1851 and the family were still there up until 1858 - they moved from Dalmellington to Kilwinning between 1858 and 1861. At the same time, though, the Dalbeth burial can't be wholly discounted as I can't find a Margaret Leonard on the 1851 census in the Glasgow/Lanarkshire area to match the death. It's possible my Margaret was visiting someone, died near there and was buried in Dalbeth. I've been in touch with Sharon before for other Dalbeth burials so I'll drop her an email and check. No harm in seeing if I can rule her out or not.
As for whether Jeremiah could have gone under another name - yes he could and yes he did! Men named Jeremiah were often called Darby due to the way Jeremiah is pronounced in Irish Gaelic. Anyway my Jeremiah did go by Darby. He was on the 1851 census as Darby Leonard and listed on some of his childrens' marriages/deaths as Darby at times and Jeremiah at other times. I have checked for a death for him under Darby though and there's nothing.
Ok full history is this:
John Leonard died in 1882 apparently aged 103! This is an old family tale I have heard many times. It took me a while to track him down as the family tale had him called Michael Leonard and from the wrong line. The story had gotten confused through time but it was that he lived to 103 and every day after his 100th birthday he could go to the pub at the end of the street in Hamilton and get a free whisky. I always thought it couldn't be true! Anyway eventually I did find a death for a 103-year-old man named Leonard in Hamilton that matched the story! His parents were listed as Jeremiah Leonard and Unknown Droogan. This man was a John though and there were no Johns on that line - it turned out he was the father of the wife of the person attributed to being his son in the story. It all got confused as his daughter Elizabeth Leonard married a man named Michael Lennan and their son ended up using the name Leonard over Lennan. I still don't believe old John was really 104 though! Mind you he must have looked pretty old for his age to get away with passing himself off as such! If he was genuinely that old he would have been born c1779 in Ireland. Here he is on the 1851 census:
Address: 84 Waterside Huts, Dalmellington
John Lenard Head Aged 53 Labourer at Quarry, Born Ireland
Margaret Lenard Wife Aged 53 Born Ireland
Mary Lenard Dau Aged 23 Born Ireland
Margaret Lenard Dau Aged 18 Born Ireland
John Lenard Son Aged 28 Rail Lan Born Ireland
N.K. Lodger Aged 62 Vagrant Born Ireland
I'd suspect he was older than Margaret but he would have to have been 70 by this point if he was really 103 in 1882.
Now the next "household" directly on the next line is as follows:
Address: 84 Waterside Huts, Dalmellington
Darby Lenard Head Aged 32 Wagon Emptier Born Ireland
Catherine Lenard Wife Aged 36 Born Ireland
Margaret Lenard Dau Aged 11 Scholar Born Ireland
Elizabeth Lenard Dau Aged 4 Born Ireland
Patrick Lenard Son Aged 6 Born Ireland
Catherine Lenard Dau Aged 3 Born Ireland
So there is a Jeremiah Leonard living basically with my Leonards about the right age to be John and Margaret's son when John's father was also called Jeremiah. Without younger Jeremiah's death I can't prove he was his son but I think it's a very good bet he was. It's an unusual name and they're all living in the same place - it's hard to believe they're not closely related.
Anyway fast forward to 1861 and here's John again:
Address: 45 Byrehill Row
Mick Limmon Head Aged 35 Coal Miner Born Ireland
Elizabeth Limmon Wife Aged 36 Born Ireland
Patrick Limmon Son Aged 11m Born Kilwinning, Ayrshire
John Lennard Father-in-law Aged 60 Labourer Born Ireland
Margaret Lennard Sister-in-law Aged 24 Born Ireland
John is going down in age here - he's just 60 now! Only his daughter Margaret from the 1851 census is there and he is listed as a widower so we know wife Margaret has died. She is listed as deceased on Elizabeth and Michael's 1858 marriage too so we can narrow her death down to between 1851 and 1858 and, as I say, there's no sign of it in statutory registration so presumably it was 1851-54.