The Avern family did seem to intermarry and as well they seemed to keep naming their children with all the same names!
Anyway, Thomas Avern who married Mary Ann Avern:
Thomas 1773 - 1852 & Mary Ann 1789-1870
Thomas' parents were Thomas 1728 - unknown and Elizabeth Abbotts unknown dates
Thomas senior's parents were William 1688-1776 and Susannah 1690-1759.
Mary Ann's parents were Thomas & Mary - so far I have no dates for them. Her siblings were Thomas 1791- and Frances 1793- who married William Gardner.
Mary Ann's father could be any number of Thomas Avern as both William and his son Clement mentionned a Thomas in their wills, while another William who died in 1811 also had a son Thomas and a grandson Thomas. We haven't figured it all out yet!
"Thomas and Mary Ann Avern (#86) were married in 1814 (he being previously married to Amey #90 died 1808) This Thomas lived at the Malt House and was miller of the Tom O The Wood Mill. Described in 1841 census as "Malster". In 1851 Thomas was 78 years and Mary Ann was 61 and their daughters Mary Ann aged 31 and Harriet aged 26 lived at home. By 1861 Thomas was dead and Mary Ann Snr farmed 14 acres with the help of her daughter, also Mary Ann."
(source Rowington cemetery fiche)