It's not at all personal, it's a cold factual assessment of this bit:
A further complication is that my host has disabled htaccess inheritance in order to facilitate their custom access logging package. Therefore most of the www htaccess data has to be repeated in the subdomain htaccess file. (Very inefficient, but apparently my fellow virtual hosters can't live without tagged access logging!)
There are many, many hosts that get "custom logging" working right -- without crippling their customers...
Also, if you could 'blow up' custom access logging on the server simply by adding "RewriteOptions inherit" to a .htaccess file, then that's a potentially-serious 'security' problem... :o