There's no marriage of a HOWELL to either a (--?--) HONOUR or a Honour (--?--) in Hunts Marriage Index. But as they were non-conformist they could have travelled some distance to attend the church in St Neots (St Neots was always in Hunts, never in Beds). I see that at Samuel's three convictions, where he was resident either at Eaton Socon, Beds (across the river from St Neots) or at Eynesbury, Hunts (which is now part of St Neots).
So the family could have been from Hunts or from Beds, or even from Cambs which is only 5 miles from St Neots. I can't see a suitable marriage on the IGI in Beds, nor in Hunts
Unfortunately Samuel was the only Howell entry in the St Neots Independent Church.
I can't see any obvious burials in Beds Hunts or Cambs, nor any suitable Howells in the 1841 and 1851 censuses
I'm stuck!
David