Sorry, i think I'm talking semantics here. It was just your use of the term 'new use' which is, in application parlance referred to as a 'material change of use'.
I just wanted the Op to be aware of the correct term if they were asking.
The truth of the matter is, on many occasions pubs just use the surrounding land in whatever way they use. Especially if the licensing application's red line takes in the curtilage of the site rather than the building itself.
This then leads to it being very difficult to prove whether there is a material change of use.