Just to report back, she now seems much more content after a small increase in her milk intake (up to 30oz) and a reduction in her solids.
I'm surprised she was seemingly so affected by a such a slight reduction in her milk intake but she has been on the same amount for 3 months now and she is a big girl.; Perhaps she has learnt to just about get by on this moderate intake and really feels even a slight reduction?
Anyway, I'm a little confused about how best to move forward now. We will slowly and carefully vary and increase her solids intake and keep her formula at the same amounts unless she starts to refuse to finish her bottle (she never does this). Is this best? I know that she should be taking much less formula once solids are established but is it best to wait for her to cut her intake by herself? I suppose she may be readier to reduce her formula for herself once she starts having some protein with the solids. Perhaps this might supply some of the things that she could clearly only get from milk and not from the rice, fruit or vegetable.