I took up Ken Willis's advice and now have a demo lock box.
“As an interim measure lock boxes are available from Graseby @ £65 ish. One draw back (or benefit) is that it locks out all controls as well as securing the syringe ”
First impressions are favourable its light strong and reasonably compact. I'm in the process of attempting to acquire a basic L lock anti-siphon extension set. I think this combination considerably ups the safety of these useful wee devices although there is still the 1 and 24 hour and set-up issues.
Thanks Ken.
Bill