Hi again - I've just dealt with my webhost (webhostuk.uk.net) who have been awesome, and fixed the problem for me.
they say that the problem was with my htaccess file not being correct, and they took the one from the SS directory and replaced mine, and now all seems to be ok.
I'm not sure if this is something that should happen automatically or not, and they say that mod_rewrite is always enabled by default on their servers, so I'm not sure if the problem was with the SS install or something I did wrong.
But basically, replacing the htaccess file with the one in the SS directory solved the URL rewriting, and enabled me to do the dev/flush which has let me view my other page templates
now to get stuck into silverstripe!
:-)
edit: here is what my htaccess file now looks like
### SILVERSTRIPE START ###
<Files *.ss>
Order deny,allow
Deny from all
Allow from 127.0.0.1
</Files>
<Files web.config>
Order deny,allow
Deny from all
</Files>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_URI} ^(.*)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* sapphire/main.php?url=%1&%{QUERY_STRING} [L]
</IfModule>
### SILVERSTRIPE END ###