Let the fun begin !!! ???

[Neale]

I'm not sure if I would bother with the relay switching if you are using a reasonably large value of R. Use something like 4K7, 3W, wired directly to the capacitors, and save a relay contact and associated wiring? Probably about the same current draw as three quiescent drivers, so maybe not worth the effort, but it would drain down the caps even if everything else were disconnected during testing. I must stick a meter across my power supply some time and see what happens - I don't have any bleed resistor in place.