Yes you're correct.
The standard phraseology for an instruction to a pilot to track the runway centreline after departure is "climb straight ahead".
This was changed in MATS Part 1 a couple of years ago.
The only time that "heading" is used is with the appropriate number of degrees e.g. "after departure fly heading 090".
The term "climb runway heading" or "after departure maintain runway heading" is now obsolete. For a go-around the correct phraseology is "on the go-around fly heading xxx".
Yep I am a tower and approach radar controller!
[This message has been edited by PPIMan (edited 05 June 2001).]