Phil, just out of curiosity (Im not looking for a job
) do you post your minimum....or even perhaps desired qualifications/hours on your website?
Not having looked for a fair old while I'm not in the know. I take your point about not having either the time..nor the inclination to reply, when clearly you have no requirement etc.
One approach that requires a little more time and effort..is the personal approach..take your details..find out who to contact..then arrive on their main entrance (office!) when you know they are there...(this got me my first job)...beware however to tread carefully..and not be too pushy, horses for courses as they say.
Just my thoughts...I know I've sent loads of CV's over the years...and probably got only 10% replied too.
Cheers H