It sounds like you're doing the best you can there, Malcolm.
As you know, the Alternative Method does not activate the DUT, and so therefore is not comparable to all 60601 tests (especially leakage currents) ...
however, for occupied beds and similar items I should imagine it's more or less ideal!
And ... I'm guessing that where you are, mains polarity is not an issue (
ie, can be either way around).
I have encountered the "split phase" situation myself in strange locations many moons ago; our tester didn't pass it's Self Test!
But (more importantly), how good is the building earth in the places you mention?
Lastly, are those mains cables fixed, or detachable, I wonder?