Hi,
Thought I would post to say It was all fixed. It took some to-ing and fro-ing with our external hoster as every time they sent me a copy of the files they were corrupt. In the end they very kindly gave me access to the panel for their server so I could hop in and pull the files I needed myself.
Adding that copy of the database and files to the server and hey-presto it all worked.
So not sure why they were always ending up with corrupt files but it won't matter in a week or so.
Thanks for everyone's help here.
Cheers,
John.