Expect you will have investigated the village of Horningsham,by now.But, would just mention that its part of the Longleat House estate,hundreds of farm labourers and an enormous list of servants of every description kept it all going in your time frame 1830s/1860s.
Have had a search but date of births vary a lot,but would imagine Mary would have had some sort of sponsor to baptise her bastard child at St Denys Church which is right in Warminster.
However there is one Charles Foreman who married Julia Mary Churchill 1867 Warminster,her father Cornelius Churchill was publican of New Inn Boyton 1861. Needs looking at.