Hi
A gardener isn't really going to be someone who lived in a mansion and had a butler. To have a butler you would need a household of servants and be of some wealth. You would expect such a family to have privately educated their children and be of some standing in the community. Even if when this man died servants some how obtained his will depending on the date, the will would have to be proved either in a church court or in London from 1858 onwards the Principal Registry Office. This would take time. Anyone during this period would be able to contest the validity of the will. You might expect a family of some wealth and standing, if the man concerned had family, to be able to successfully contest the validity of the will and so it wouldn't prove. Only if it did prove would the beneficiaries in this case mere servants, be able to touch the estate and take it away from the family in situ, if there was an immediate family in situ. If the will proved then there would be a record of that fact.
Nothing in the Prerogative Court of Canterbury or the Consistory Court of London for Thomas Bearman. The indexes online that would cover the Principal Registry are not complete for the period 1858-1861.
The Thomas Bearman death registration in Greenwich registration district (then in Kent) is possibly this man on the 1851 census.
1851 census HO107 1584 folio 9
Field House New Cross Road Hamlet of Hatcham St Paul Deptford
Ann Wicken 26 Unmarried House Servant Deptford Kent
Charlotte Wicken 19 Unmarried House Servant Deptford Kent
Thomas Beerman (could be Bearman) 60 Married Gardener Essex
Possible second marriage for Thomas in Lambeth in 1844 (widower and gardener) with his wife living in 1851 in Hatchman HO107 1584 folio 16
It looks like the family who owned the property 'Field House' were away on census night with three servants remaining. There is a picture of Field House on this website
http://thehill.org.uk/society/history.htmPigots Directory of 1840 for Deptford lists
STANSFIELD Josiah esq, (magistrate), Field house, Newcross
http://janetandrichardsgenealogy.co.uk/Pigots%201840%20Kent%20-%20Deptford.htmlJosiah appears on the 1841 census HO107 488/17 folio 7 living on New Cross Road but the house on this census is not named. He is of independent means, living possibly with a wife (no relationships given on the 1841 census) three servants but no other family shown.
This leaves a further possibility that the story actually concerns the Stansfield family with Thomas a servant in the household and therefore knowledgeable about 'the event' or even perhaps involved in it, though Josiah Stansfield looks to have had Yorkshire connections and possibly died there and not in Kent.
You might want to obtain a copy of Thomas Bearman's death certificate to see what circumatances he died in.
Regards
Valda