I presume I need to use check in desk as I have a UA confirmation/ticket?
I would have thought so, don't think bmi's self check-in would quite handle that, even though in theory you're supposed to self check-in as you're on a bmi standard fare.
I'm guessing both flights issued on a single ticket with one booking reference, otherwise you won't be able to through check-in your bags with bmi.
On UA B is E+ is B on BMI standard econ or premium?
It's a one-class service, but 'B' on bmi is a standard economy fare class anyway.
As a *G can I bring my wife (no status - (*A that is) and teenage daughter into the lounge?
Hmm... technically no, as you're only allowed one guest, but it wouldn't hurt to ask. MME isn't the busiest of airports.
...call centre in India was totally useless.
Yup. Aren't they all!!