Of course, I couldn't begin to start preaching to those who work Nottingham East Midlands Robin Hood Tees Valley radar,
, but from a pilot's point of view I would think that if you didn't want me to do something now, you'd say 'pilot's discrection'. From a safety point of view, there can only be two time frames, do it (now) or do it when you want to (pilot's disctrection, when ready etc). There should be no grey area.
In the case quoted, the use of the word 'now' would have removed any ambiguity. The same result would have been achieved by putting the climb clearance first.