simonhoward, I hope the lodger/language student thing works out.
I know what it's like to work 7 days a week for financial survival. For over a year I had a full time job, mon to fri and ran a stall at weekends. It's not fun. We got out of this rut by moving to a cheaper area - bigger house, too. The best thing we ever did.
I have to say that if mumsnet had been around when I was working these hours I would still have felt 'qualified' to contribute. And I think some of the other mumsnet contrubuters put in very long hours, too. It is not just a working dad thing.
Luckily, I arranged my working life so I could see my toddler son for at least three hours a day (he had a late-ish bedtime) and usually spent a day with him at weekends. Not always possible for everyone working these sort of hours. I could also look back to times with him when I was working less, or not at all, so I had that knowledge and closeness to draw on. You presumably have similar memories stored up. I'm sure you treasured the time you had with your dd inbetween your two jobs, and when you were working fewer hours. And of course you have holidays to catch up on time together.
I am sorry that you feel you are missing out on your daughter's development, but I simply cannot believe that you have no knowledge of her routines, personality and preferences. I hope that you feel 'brave enough' to enter a variety of other mumsnet discussions. I see you and startC have been making inroads into some of them recently.