I think it unlikely that the parish register will have any further information, but it may be worth using the search services of the Northamptonshire Record Offfice to find the entry.
Who are the witnesses listed on the marriage certificate?
On the 1901 census Kate MORGAN (nee WALMSLEY) is living with her parents in Northampton (born in Towcester). Her infant daughter Elsie is with her. No sign, though, of Thomas.
Pennie