There is a marriage in Winchcombe of a Kathleen M BOX and a John A JOHNSON in 1930 which appears to be a reasonable fit.
This couple is living in Colerne, near Chippenham, in 1939 with one child. Her birth date was given as 9 Feb 1904 which which is slightly inconsistent with Kathleen's birth registration in Q1 1903. That said, it does seem unlikely that two Kathleen M BOXs would co-exist near Winchcombe.
Personal
Family
World
Date
Age*
Event
Place
Q1 1903
0
Winchcombe, Gloucestershire
2 Apr 1911
8
Laverton, Broadway, Worcestershire, England
13 Jan 1918
15
 
Place of death recorded as East Africa, but most likely Dar es Salaam.
 
Dar es Salaam, Dar es Salaam, Tanzania
Q2 1930
27
Winchcombe, Gloucestershire
Q3 1931
28
Evesham, Worcestershire
Q3 1933
30
Winchcombe, Gloucestershire
Q3 1939
36
Shipston on Stour, Warwickshire
29 Sep 1939
36
High Street, Colerne, Chippenham, Wiltshire, England
Q1 1964
61
Evesham, Worcestershire
Q4 1971
68
Bath, Somerset
18 Jun 1977
74
15 Kings Road, Evesham, Worcestershire, England
Dec 1984
81
Taunton Deane R.D., Somerset
Q4 1994
91
West Oxfordshire R.D., Oxfordshire
Documented age, Calculated age, Estimated age>