Thanks everyone, I have felt much more hopeful today. Last night she went to sleep at just gone 7, woke a couple of times before 10 but settled herself, slept til 3.15am, fed, went back to sleep til 6.30am, then came into bed with me and dozed off again until 7am. Lovely.
I tried to replicate yesterday's naps, today, but of course it didn't work. It went like this:
7am A
10.05am S 45mins
10.50am A she absolutely could not stay awake a minute longer here, she was grizzling and putting her little head on my shoulder trying to sleep bless her, and actually fell asleep in my arms in the time it took me to carry her upstairs
1.25pm S 1hr20mins only, wouldn't resettle
2.45pm A
I couldn't squeeze a catnap in, so bedtime was 6.10pm. She woke up and I had to go in and feed her just now, at 10pm.