OK after dozens of retries I managed to get the patch to install. Seems I need a clean install but RUN the game first, get into the main menu and setup the config but don't start a new game yet. Also had to manually drag from the rar file all the folders and files, into the game folder, as unzipping directly in there correctly, or unzipping manually and carefully copying them in just gave the same errors again I mentioned above.
Anyway the game now works with the patch! However if I install the Blue Sun Mod afterwards it DTD's and barfs when the game runs and I have to reinstall and do it all again without the BSM.
Seems awful finicky this game and the mods inherit that too
Thanks for making the changes and I hope this ramble helps some people in future.
Cheers