Aha! You got it!
I didn't think to look there... and the extension shows it is 7.3.3 so:
1) Clearly, the upgrade package didn't overwrite that bit
2) and logically, the report was correct.
So I did this:
a) Reinstalled the upgrade package. No joy.
b) 'Fudged' it by manually updating the 7.3.3 entry in the Host>extensions to 7.4.0. No joy.
c) Downloaded and overwrote the online files from my working site to this local site. No joy.
conclusion: 1) isn't correct, but 2) probably is.
NB: I'm pursuing this only because I have neat bit of JQuery that insists on the script being in the physical location of the result. (It's a countdown thing...).
In order to do this, I need to set the flag that allows scripts in the HTML Editor.... Which I can't currently do (on my local test environment only... the online live sites are fine...)
So I took a look at both XML files and the database that might hold the flag... couldn't find that either!
I suspect I can resolve this by introducing the ckEditor as suggested here - but that would be giving up!!! :)
Any other suggestions?
PS. Thanks for the support.