Hi,
Boundaries have changed a bit parts of Berkshire & Oxfordshire have at times been in and out of Bucks, but Hampshire and Bucks do not touch, so it very unlikely to mix up these counties. However I can find No Jabez James on the 1841 census in Hampshire, there is on on the 1851 born Hampshire and married to a Maria, could not find him in 1861/71/81. His birth place looks like Bormois, Hampshire, but I have never heard of it, and if it did exist, it does not now, possibly it was misheard by the census taker.
Love Vita.