Well, I have taken the decision to switch to a new web hosting company. The repeated "500 internal server error" events (which included about 12h solid early this week), coupled with totally inadequate response for the "technicians" at my current hosting company have swung my decision to act. By totally inadequate, I mean that I received a prompt "cut and paste" response on 13th July, and not a whisper since.
I'll migrate the site as soon as I can make a backup of the database and files. Unfortunately, this probably means the site will be moribund for a few days. This affects both the main Flies & Bikes site and the Wonderful Life blog.