Joy it all came together when I realised that the marriage did not take place in the Parish of Mere, but the Registration District of Mere

. There are 12 Parishes so starting in alphbetical order...............I came up with (no prizes for guessing which parish I looked up last)
In the Parish of Zeals 17 Apr 1911 Arthur Ernest Gatehouse, 21, bach, lab, Gillingham, Frederick Gatehouse, Blacksmith married Ethel Emmeline Green, 21, sp, Zeals, Albert Green, Mechanic, by Banns. Witnesses were Alfred Green and Clara Green.
Zeals Church was built in the 1840s and prior to that marriages were in Mere.
Other Gatehouse (G) marriages in 1911
17 Apr George G, 23, bach, lab, Mere, John G, lab and Kate Ings, 42, wid. Mere, Tom Ings, Engineer
16 Sep Charles Allen Hurley, 29, Stourton, Philip Hurley and Lily May G, 25, Stourton, Tom G
Cheers Dave