If you look at the parish registers on this site you will find Benjamin White buried at Christchurch on 9 Feb 1952 age 81 and Lucy White buried at Christchurch on 25 March 1953 age 77 (of The Bungalow, Joyford).

There is a prior thread which discusses burials at Christchurch at http://forum.forest-of-dean.net/index.php?id=48926. You might find some useful information there.

The Parish Registers tell us that Benjamin and Lucy were buried at Christchurch and given the dates it is most likely that they were buried in the new part of the churchyard. In fact the entry for Lucy includes the following "new ground re-opening" which suggests that she was buried in the same plot as Benjamin in the new part.
There is a database of the Memorial Inscriptions of the Old Churchyard on this site and you will find an entry for William White, Benjamin's father as follows:

Location Row I
Reference Number 108
Type Headstone
Surname WHITE
First Name William
Day 9
Month Feb
Year 1910
Age 66
Details In Loving memory of William White the beloved husband of Eliza White of Joyford who died Feb 9th 1910 aged 66 years Also of the above Eliza White who died Nov 14 1934 aged 86 years
Notes
Parish Christchurch

Looking at the transcript of the M.I.'s for the new part which is also available on this site (see Documents and Articles/Miscellaneous Documents) there is no entry for Benjamin and Lucy so contact with the Parish will need to be made to establish the position of the burial site. This webpage may be of help:
http://www.christchurchfod.org.uk/team.html