John and Jane Keen was christened their daughter Martha at Saint Michael, Coventry on 8 Aug 1794 at Saint Michael, Coventry, Warwick, England. In the 1851 census, Martha said she was born in Combe Fields which is 5 miles by road from Coventry (half that distance as the crow flies) and 10 miles from Kenilworth.
Combe fields is a parish with scattered houses, but no village. The ruins of a twelfth century abbey and the local manor were both owned by the Craven family. There are still several farms in the area so I am guessing John Keen was probably a farm labourer.
There are two entries for a 'John Keen' marrying 'Jane' in Coventry:
John Keene married Jane Taverner at St Michael, Coventry on 14 Apr 1780
John Keen married Jane Beaufoy at Holy Trinity, Coventry on 13 Aug 1781
Known children:
John s/o John Keene and Jane Christened at St Michael Coventry on 12 Feb 1781
Esther /d/o John Keene and Jane Christened at St Michael Coventry on 14 Sep 1783
Jane d/o John Keene and Jane Christened at St Michael Coventry on 20 Jan 1789
Benjn s/o John Keene and Jane Christened at St Michael Coventry on 9 Nov 1790
Martha c/o John Keen and Jane Christened at Saint Michael, Coventry on 8 Aug 1794