The grounds of Halton Grange are today a public space.
The "church on the island" referred to in the message below, is Weston Point church (now deconsecrated and closed). This was said to have been the only active church in the world built on an uninhabited island ! ( It is completely surrounded by canals and dock basins.)
The message reads:-
Near Runcorn Ches
Have had a pleasant day here. I saw the church on the island and also visited Weston Parish Church. Most interesting .