Ah, that might well account for it. Yes, my girlfriend and I have HHA between us. My account was debited 127K miles rather than the 150K I was expecting and I couldn't find any reason for this so was wondering if I had been the recipient of a mistake in my favour. Thank for clearing up my confusion.

Guess I'll just have to live with the warm, albeit fading, glow of the previous mistake in my favour. That was my first reward booking and my first time in Club - I thought the miles might have been debited after the flight, but they never were.