lisa glas she had another sleep yesterday!
remember sleep creats sleep, and been overtired makes it very hard for them to settle off to sleep, they simply cant do it!
i agree that 1 sleep at 7 months isnt enough i think sophie was still having 4 at that age!! which was a little extreme i know! but she needs at least two!

like janie said id try a bedtime routine, if sophie is going to go down at 7pm we do dinner at around 5pm, bath at 6.30, boob, which now is around 30 secs then bed

we've always done the same routine, even if we miss the bath some nights, she still knows when its bedtime

goodluck with the routine and let us know how you go