Hi Jan
Although Jersey is only 9 miles by 5 miles, it is divided into 12 Parishes, each with its own Parish Church and Parish Hall. Civil Registration started later than the UK in 1842, so up until then Parish records still exist, going back in some cases to the 1500's. So St Martin's is a Parish and has its own Parish Church. It was, and still is, a very rural Parish in the north east of the island and is the closest to France being only about 12 miles away. France is clearly visible and you can see the lights of cars at night time.
The Parish Records and Civil Records do tend to mention both the husbands surname and the wife's maiden name. In fact they still do today. When I complete my tax return I have to state my wife's maiden name and when we bought the house it is again done in her maiden name!! Sadly though the Parish Records do not mention an abode. It is possible though by other means to establish who owned a property. All Land Registry is on a computer system but not available over the internet.
The reason why I suggested an army connect was because England was still at odds with France at that time and Jersey held a strategic position in their conflict. Consequently the UK sent over troops regularly and there are a number of Garrisons in St Martins.
As regards help with Somerset, S Wales etc. My own family on my fathers side come from Bridgewater and moved to South Wales in the mid-1800's. I was in fact born at Caerleon and lived my early life in Cardiff. My mother's side come from deepest Montgomeryshire and I have produced their trees going back to the 1700's - but many thanks for your offer.
Stewart