The plumber arrived 2 hours late and muddled around, unable to find the problem. Eventually he left, saying he'd come back in the afternoon with a different pump and fix the problem.
He did. Only trouble was he fused out all the power points in my house. I have an electrician coming Monday AM but till then I'm PC-less, coffee-less and oven-less and definitely happy-less, so please forgive me if I make less sense than usual over this weekend.
I'm using my daughter's PC to answer my email.
So if I miss anyone I should have replied to - please accept my apologies. Once I'm back in the electricity powered generation, I will get back to you.