There isn't usually an age on registers from this date. From 1754 to 1837,they look like these
http://www.archivecdbooks.org/resources/registers/7marpre1837.htm
Free Reg includes the names of the witnesses and usually notes anything extra that the clerk has added.
Marriage date 19 Jul 1787
Groom forename John
Groom surname GILES
Bride forename Phoebe
Bride surname SANDERS
Witness1 forename Elizabeth
Witness1 surname MASCOE
Witness2 forename John
Witness2 surname PIPPER
There are two burials that may very well be them. The only other Phoebe is Phoebe and John's daughter baptised in 1788.
There is an earlier John, buried in October 1789 with no age give but this may well be a John, s of William and Mary Giles baptised in July. Another John son of John and Phoebe was baptised in September 1790.
Burial date 13 May 1821
Burial person forename Phoebe
Burial person surname GILES
Person age 60
Burial person abode Bromley
Transcribed by Carrie Van Kessel
Credit Carrie Van Kessel
File line number 531
(so born c, 1867)
Register entry number 502
Burial date 13 Dec 1840
Burial person forename John
Burial person surname GILES
Person age 78
Burial person abode Bromley
Transcribed by Carrie Van Kessel
Credit Carrie Van Kessel
File line number 502
So born c.1761