That's because subversion sets the character encoding to UTF-8 in the http header which overrides the character encoding in the file. It'll be fine elsewhere. I don't know if it's possible to stop subversion from doing that. Although ideally, we should use character entities for all anything that isn't ascii.
So does this mean that a release using a zip from Sourceforge will display OK.
Yes.
The symbols used above are trivial and not important, but does it mean that some more significant symbols like math and greek say will not display right?
I don't remember this being a problem with the Math development, but perhaps we never used SVN to move html files?
We did, but same issues there with any non-UTF-8 character that's not encoded as a HTML entitity (all the special math symbols are).
Not a problem with pdf I presume.
Or should we use a different way of specifying symbols to avoid this?
Probably not, it's an SVN SNAFU rather than a real issue. TLA overloading yours, John.