Have you come across a Thomas Garrod who was an exciseman in Norfolk at least from 1818; he died in 1828. In 1819 he and Elizabeth had a son Henry baptised at Wells-next-the-Sea. This Henry was my ggf.
Beyond a few references in the records of the Board of Excise held at Kew I am stuck on Thomas; perhaps the variant spellings of the surname do not help.
Happy to exchange such information as I have.