The interesting thing about the 1841 Merridens is by 1851 they seem to have turned into Freemans if only for the census.
1851 census HO107 1715 folio 95
Bridge Row Bovingdon
George Freeman 27 Bovingdon Head Unmarried Ag lab
Fanny Freeman 37 Hemel Hempstead Sister Widow Straw plait manufacturer
Henry Freeman 19 Bovingdon Brother Unmarried Ag lab (1861 census a married Meriden in Bovingdon)
Joseph Freeman 17 Bovingdon Brother Unmarried Ag lab
Keziah Freeman 7 Bovingdon Niece Straw plait manufacturer (1861 census a lodger and a Merrington in Hemel Hempstead)
Thomas Freeman 4 Mo Bovingdon Nephew
MERRIDON, Henry
Birth Date: 2 Apr 1832
Christening Date: 25 Sep 1842 Bovingdon, Hertfordshire
Father: William MERRIDON
Mother: Fanny
MERRIDON, Joseph
Birth Date:12 Apr 1834
Christening Date: 25 Sep 1842 Bovingdon, Hertfordshire
Father: William MERRIDON
Mother: Fanny
WILLIAM MERRIDEN
FANNY FREEMAN
Marriage: 19 DEC 1831 Bovingdon, Hertford
Births Dec 1850
Merridon Thomas Hemel Hempstead 6 545
Births Sep 1843
Merridon Kesiah Hemel Hempstead 6 504
Regards
Valda