Hello, Diane,
Why not take a chance & ask Kew yourself for a copy of the entry for the birth of Katherine Margaret Probert & the death of her mother, as you can provide the File no. etc. I do believe they do this but at what cost, I cannot say. I think it is worth the cost of a letter & an SAE or IRC.
The Public Record Office,
Ruskin avenue,
Kew,
Richmond,
TW9 4DU
Good Luck,
Meliora