There is a tree on Ancestry for Rebecca but there are no sources given for her marriage/birth/parents' marriage apart from what would be obtained from SP indexes.
Here it has her death as 1966 Mexborough, England. Parents down as dying in New Zealand.
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PS - just noticed that it's your tree
Added - you really must try and get hold of (purchase or a visit to Scotland) the marriage and birth certs or you won't really be able to proceed much further and I don't think you have the correct parents. While some of us don't mind using the odd credit to look at online certs, these are 'order only' and more expensive.