Rich, just ask ATC mate, they're just normal humans and the radio is there to be used. "Can I continue the approach to 500' and then go-around or do you want me to go-around now". In the time it took you to ask that and for them to reply, even if they wanted you to discontinue the approach immediately, it would have only made a few feet difference and certainly not something that would effect the blokes working on the ground.......that is, of course, assuming you're not doing you PPL training in an F-18
There's certainly a time to use absolutely correct RT phraseology, equally there are certain rules that need to be known off-by-heart but in a situation like this, just keep it simple and do just what you'd do if you weren't in an aircraft
