Hello John...welcome back
We've all barked up the wrong tree before, try not to worry too much...
Not sure how much use I am going to be, on first glance I can't see your John Harrisson in the 1861 census, or a remotely matching baptism anywhere yet either....
I did have a look at the Kent Parish registers on Find My Past, and the below Harrissons are the only ones I could find in that local area between the years 1785-1805, excepting the Challock baptisms:
St Mary Magdalene, Davington, Kent
Baptisms:
10 Nov 1793 - Sarah Harrisson daughter of William & Frances Harrisson
12 Jan 1800 - George Harrisson son of William & Frances Harrisson
28 Mar 1802 - Mary Harrison daughter of William & Frances Harrison
21 July 1805 - James Harrisson son of William & Frances Harrisson
St Mary, Norton, Kent
Baptisms:
6 Mar 1786 - William Harrison son of William & Frances Harrison
25 Apr 1788 - Frances Harrison daughter of William & Frances Harrison
28 Nov 1790 - Robert Harrison son of William & Frances Harrison
St Michael & All Angels, Throwley, Kent
Baptisms:
6 Mar 1796 - James Harrison son of Robert & Mary Harrison
29 July 1798 - Henry Harrison son of Robert & Mary Harrison
1 Jun 1800 - Frances Harrison daughter of Robert & Mary Harrison
St Peter & St Paul, Charing, Kent
Baptisms:
19 Jan 1786 - Frances Harrisson daughter of Robert & Mary Harrisson
6 Dec 1787 - Robert Harrisson son of Robert & Mary Harrisson
23 Dec 1789 - Elisabeth Harrisson daughter of Robert & Mary Harrisson
14 Dec 1791 - George Harrisson son of Robert & Mary Harrisson
11 Dec 1799 - Elisabeth Ann Harrisson daughter of William & Elisabeth
4 Oct 1801 - William Harrisson son of William & Elisabeth Harrisson
Not a single John
I did find your John Harrisson's burial as below though:
St Mary, Stalisfield, Kent
John Harrisson buried 7 Aug 1881, aged 87yrs, abode: Charing
I couldn't see any Harrison/Harrisson baptisms in Stalisfield itself during the right time period...
Curious....
I guess he could belong to William & Frances Harrisson who had children in Norton & Davington between 1786 & 1805, as the is a gap between 1793-1800 when they could have been in another village perhaps. It is the right time period for your chap who was born abt 1794-96 by the census records and his burial.
Nothing concrete to go on I'm afraid...I'll let you know if anything else turns up
Jenny