In reply to Karl Lunt:
As a generalisation you are correct, however in some circumstances, in Scotland you may take access via private drives, see last sentence of:
'3.16 Some larger houses are surrounded by quite large areas of
land referred to as the “policies” of the house. These are
usually areas of grassland, parkland or woodland. Here, too,
you will need to make a judgement in the light of the particular
circumstances. Parts of the policies may be intensively
managed for the domestic enjoyment of the house and include lawns, flowerbeds, paths, seats, sheds, water features and
summerhouses. Access rights would not extend to these
intensively managed areas. The wider, less intensively
managed parts of the policies, such as grassland and
woodlands, whether enclosed or not, would not be classed as
a garden and so access rights can be exercised. In these areas
of grassland, parkland or woodland, you can also exercise
access rights along driveways, except where the ground
becomes a garden, and pass by gatehouses and other
buildings.'
However the OP was using a farm track, so hypothetically if it were in Scotland access would have most likely have been permissible (see last 4 bullet points in particular):
'Where and when you can exercise access
rights?
2.2 Everyone, whatever their age or ability, can exercise access
rights over most land and inland water in Scotland, at any time
of day or night, providing they do so responsibly. These rights
do not extend to all places or to all activities (see paragraphs
2.11 to 2.15). Provided you do so responsibly (see Parts 3 and
5 of the Code), you can exercise access rights in places such
as:
• hills, mountains and moorland;
• woods and forests;
• most urban parks, country parks and other managed open
spaces;
• rivers, lochs, canals and reservoirs;
• riverbanks, loch shores, beaches and the coastline;
• land in which crops have not been sown;
• on the margins of fields where crops are growing or have
been sown;grassland, including grass being grown for hay or silage
(except when it is at such a late stage of growth that it is
likely to be damaged);
• fields where there are horses, cattle and other farm animals;
• on all core paths agreed by the local authority;
• on all other paths and tracks where these cross land on
which access rights can be exercised'
Source SNH website