Paul, just to repeat my offline response for the benefit of others with similar issues:
First, don’t waste effort re-uploading or a fresh install. Neither are likely to make any difference. They rarely ever do. It is more important to identify the cause of the problem first.
The first point in the upgrade instructions, about a potential fatal error, is likely to be your issue. Many servers have error reporting disabled by default, so a blank page us a distinct possibility. There should be an error in the server logs though.
If that doesn’t help give me the URL and I’ll take a look tomorrow.