Hi Richard,
I've registered on your site as jaudette, if you find me on the member list and click the gear icon to get to user management, you can add me temprorarily to the Administrators role and I'll have a look at the error log and see what I can figure out.
Those items you posted from your log are from back in february (or else the server has the wrong date/time). It makes me wonder if the log is still updating. Possibly folder permissions changed and the log can no longer update and these folder permissions can cause the kind of forbidden access error you are talking about.
If you want me to look around for issues in your hosting control panel, you can email me a link and credentials at joe dot audette at gmail dot com
I'll do a brief investigation, if I can solve it quickly you could buy me a few beers and call it even, if it turns into more I'll give an estimate by email.
Best,
Joe