Yes, this seems to be the correct identification, as there is reference in a parish newsletter in Sussex to "Isobel Treherne, Fr Tom's Mum who died on Sunday" [30 June], and it would appear that late Mrs Treherne's eldest son is a Catholic priest, Canon Thomas ("Tom") Treherne.
The
peerage.com website gives the names of ten children of Mrs Treherne, viz:
Mary Treherne b.1952
Thomas Treherne b.1953
Patrick Treherne b.1955
Henry Treherne b.1956
Stephen Treherne b.1958
Catherine Treherne b.1960
Jerome Treherne b.1962
Margaret Treherne b.1962
Frederick Treherne b.1967
Robert Treherne b.1972
Margaret was born in 1967, not 1962 as shown on the
peerage.com, and it seems that she was a triplet with Frederick, who appears in the above list, and William, who does not.