BB.
This seems to happen universally in UK airspace. E.G. I check in:
"London, Callsign, FL 65 climbing FL 80, Heading 085."
ATC response (assuming no change in clearance) is generally something like:
"Callsign, climb FL80, continue present heading."
or less often:
"Callsign, climb FL80, continue heading 085".
In the former case my response would have been:
"Climb FL80, continue heading, Callsign".
In the latter case, it would have been:
"Climb FL80, continue heading 085, Callsign".
This seems consistent with the idea of reading back clearances. In the first case I've been told to not change my heading, so that's what I've read back. In the secong case I've been told to fly a specific heading (which coincidentally happens to be what I was already doing), so I read back the specific value.
If I'm understanding you correctly, you are saying that its OK for ATC to tell us to continue a heading, but that we must specify what it is when we reply, otherwise you'll have to ask us.
This seems like a different standard for ATC versus Pilots. Broadly, if its not OK to simply say continue heading then this should result:
"London, Callsign, FL 65 climbing FL80, heading 085"
"Callsign, Climb FL80, continue present heading"
Now I would have to say:
"Climb FL80, confirm its heading 085, Callsign"
etc.etc.
Now I'm not trying to split hairs or have a go, I'm a big believer in standardised RT. We are trying to get as much information content into as few words as possible, therefore the meanings of phrases must be precise.
As an aside, I don't think that standardisation on RT will ever improve unless it becomes an issue for company training departments. For example, at my mob its a big deal to reply "Checked and set" rather than "Set and Checked" in reponse to a checklist item, get it wrong and the trainer will correct you, yet at the same time you'll hear senior trainers using RT phrases that have been deleted for 10 or 15 years.
CPB
CPB