Have you checked the Buckinghamshire Family History Society indexes? As well as a countywide marriage index - completed up to 1837, they have large databases for burials and baptisms. Their will database is also very useful because it includes not just the name of the person making the will but of beneficaries so it is possible to follow people named in other family's wills.
'The Wills Database is ongoing but currently contains details from more than 15,000 wills including the names of 148,000 individuals from all wills proved in the Archdeaconry Court of Buckingham from 1680-1768 and all wills of Princes Risborough testators proved in the Archdeaconry Court of Buckingham 1500-1858. Also included are details from many other wills which have been submitted by members.' http://www.bucksfhs.org.uk/There are also these two later PCC wills held at The National Archives
Will of Elizabeth Channer, Widow of Chesham , Buckinghamshire 11 November 1784 PROB 11/1123
Will of Matthew Channer, Grocer and Tallow Chandler of Buckinghamshire 14 February 1793 PROB 11/1228
Plus the Estate Duty Register at The National Archives for this will held at Bucks RO
Description Will of William Channer of Botley in the parish of Chesham, Buckinghamshire
Date October 17 1801
Catalogue reference IR 26/369
Dept Records of the Boards of Stamps, Taxes, Excise, Stamps and Taxes, and Inland Revenue
Series Board of Inland Revenue and predecessors: Estate Duty Office and predecessors: Registers of Legacy Duty, Succession Duty and Estate Duty
Piece Bucks. Archdeaconry
http://www.nationalarchives.gov.uk/documentsonline/power-search.asp?searchType=powersearchPlus these records on the A2A website held at Bucks RO
http://www.a2a.org.uk/Catalogue Ref. D-CH
Cavendish Family, Barons Chesham, of Latimer, Buckinghamshire
Records deposited in 1952
Estate Deeds Chesham Property at Tylers Hill
FILE - Lease and Release - ref. D-CH/A/261-262 - date: 24/25 March 1777
(ii) William Channer of Botley, Chesham, yeoman.
FILE - Bond - ref. D-CH/A/263 - date: 25 March 1777
Yarrall Johnson of Chichester, Sussex, bound to William Channer of Botley, Chesham, yeoman, in sum of £50 to ensure quiet possession by (ii) of property conveyed in D-CH/A/261-262.
FILE - Mortgage - ref. D-CH/A/264 - date: 1 November 1780
(iii) Joseph Channer of Chartridge, yeoman, and Elizabeth his wife.
FILE - Assignment of Mortgage: Deed of Further Charge - ref. D-CH/A/266 -date: 15 October 1792
(i) Thomas Channer of Haddle Hill, Doctors Commons, London, carman (surviving executor of will of Elizabeth Channer of Chartridge, Chesham).
FILE - Extract of Will - ref. D-CH/A/267 - date: Proved 17 October 1801
Of William Channer of Botley, Chesham, farmer, dated 5 June 1801.
FILE - Lease and Release - ref. D-CH/A/275-276 - date: 23/24 December 1812
(i) John Bailey of Botley, Chesham, husbandman (devisee named in will of his grandfather, William Channer of Botley, farmer, deceased).
(ii) Mary Channer of Chesham, widow of William Channer.
Regards
Valda
