Followed-up your suggestion and in fact there was an Isabell Oates married to a Robert Key in 1778 in Braddan. However I did not find the date of his death.

There were two Isabel Oates, one born in Braddan in 1754 and the another born in 1762 in Peel. Which is the right one? It could be either.

My feeling is that it may well be the one born in 1762 (she would have been 16 when she first married, which is not too young for that time). Also She was christened in Kirk German Parish as was her 2nd husband and her 2nd marriage also took place in the same Parish.

Are the above just coincidences?

Thanks for your time and help.