Address is:

Huntsmill Farm, Shalstone, Buckingham MK18 5ND

Closest Stations are:

Bicester North, 1 hour from London Marylebone

Milton Keynes, around 30 minutes from London Euston

Kings Sutton, 1 hour from London Marylebone

Banbury, around an hour from London Marylebone and London Paddington

Book a taxi in advance to pick you up from these stations (as there is no uber in these parts).