Hi Borderlass,
Without a specific address it would be difficult to say whether the house still stands. Next door the occupation is given as 'Shopkeeper - Grocer' so it could be one of the houses along the 'main' road to the ferry and could possibly be 'The Ferry Stores' but, and here is a big but, the Shopkeeper might not have been living at the shop.
Even with a specific address it is difficult to be certain sure as postal number do change through time.
With next door being almost certainly a grocer and the ferryman brought up by the post mistress I think there is an evens chance that the location will be close to the current Ferry Shop which incorporates a Post Office.
Ian