Hale Microtax 5 is the best meter but the ROI/Dublin? agent (SDA/mechanic24) is probably the worst installer in the business. On the plus side Mechanic 24 is open 24/7 and the meter takes an advance programme so you never have to queue for recalibration. Have mine since 2000, no bother with it.
Why wait 'till it's sealed to fit a switch, Ken. Once you remember to switch it on for the tests you'll have no problem. You can switch either the brown or black wire.