I have scoured the interweb looking for the earliest historic inserts and these are those i have found:
St. William's Church, Walderslade, Register of baptisms. Date: 1968-1973. Quantity: 1 Volume.
Records of St. William's Church, Walderslade Village, Chatham, founded 1973
Now forming part of the Parish of Holy Trinity, South Chatham (formed c.1999); formerly part of the parish of Chatham St. William and St. David (formed c.1976) having previously succeeded to the mission work of St. James' Mission Church, Wayfield (then part of the parish of Chatham, St. Philip and St. James (formed in 1962)
Final: N51° (15-8)(10-2).(5-3)(19-7)(9-13) E000° (1-11)(20-12).(4-22)(9-22)(17-14)
Good luck, happy Tupperware Hunting!
Should you happen to solve this puzzle, please keep the information you worked so long and hard to achieve, close to yourself. Cache Owners of puzzles work hard trying to find something that is not an easy thing to solve, hence the difficulty rating. If the information explodes everyone will get a smiley face. Hints are to come from myself only, however nothing extra will be told as I feel that I have already handed it to you on a platter. Thanks for understanding 
Last Maint: 05 Jun 21 - 2020, what a year!
FTF: __Plugster-uk__