[Arran]

Yes; where choke coil #56 connects to the power switch looks like about the right place to disconnect the vibrator supply. You could also rewire that switch, if it is a double throw unit, so that one side is used to switch the B+ supply off and the other to shut the A+ supply off. I would consider building the new power supply where the vibrator supply lives, but by bypassing it instead you can have the option of rebuilding it later if you want to go back to original.
Regards
Arran