>The proposed field determination is issued by DECC to all licensees involved in the field together with any others whose interests appear to be affected.

Humm...I was thinking that "field determination" is the same as 'delineation', but after reading that, I've changed my mind :)

I think it means basically just a map of the field, drawn up by the state, "utilising the geological information that is available to it at that time."