I'm afraid that I haven't found anything in the tithe records.
Looking for a landowner called Borrett seemed like the most likely option since the events happened well before the tithe survey date.
An exact search for landowner = 'Borrett' gave 255 results mainly in Norfolk and Suffolk.
There were none in Kent and I also looked further afield (Sussex, Surrey, Middlesex) without finding any. There are some Borrett records from Essex/Dagenham, but looking more closely I couldn't see any evidence that they were relevant.
If I broaden the matching criteria then a search for 'Borrett' in Kent turns up lots of 'Barratt', 'Barrett', 'Burt' etc. However if I focussed this broad search I got:
Kent/Greenwich/ 0
Kent/Woolwich/ 0
Was the case reported fully in newspapers? Such a report may give more details about Borrett's full name. When exactly was the conviction?
I can see a couple of prison records around that time for a Robert Mason, Kent, and I saw newspaper reports from March of a man of that name being convicted at Greenwich of 'uttering a forged bill of exchange for £30' and later being transferred to a prison hulk at Sheerness.