The only Evidence that I have found of Margaret Spencer to date is a mention in John Nichols Bibliotheca Topographica Britannica. The same passages also appear in the Reverend William Betham's The Baronetage of England.
The passage states that Richard Mautby Esq married Margaret the daughter of ------ Spencer Esq.
It also says that they had three sons William, Richard and Robert
The date of birth given for Margaret is before 1537
This estimate is reached because Nichols gave an extact of the South Kilworth parish register that shows the third son Robert was baptised in 1561.
Margaret's date of death is given as before 3rd March 1597, this is the date of burial listed in the South Kilworth burial register.
I have not personally seen this entry so cannot attest to its validity.
The South Kilworth Parish Registers need to be viewed in order to confirm dates.
The Mawtbey name is listed in various forms:
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