Hullo again ??
Another update:
The next time I saved changes to a page on the website it removed my manual amend from the .htaccess file. When I viewed it it only had
# BEGIN WordPress
# END WordPress in it again :(. Even though I have the settings set to /%postname%/ it just seems to remove whatever’s there. V Strange
Anyway, to keep my manual bodge in place I have removed any write access to the file so that the links work in the mean time
I’d love to do a proper fix rather than this bodge – so if anyone’s got an idea of why the built in function is mucking this up then I’ll have a play around and see if I can get it working properly.