Tracey- try her in a pram/bassinette in a warm, dark, quiet room? I suspect overstimulation also and then they get overtired and it is SO hard then for them to sleep. I was in you shoes 6 months ago with DD who stayed awake evry night from 9pm till about 4am and we wondered every night why she couldn't/wouldn't sleep and we were trying EVERYTHING to get her to sleep- hence the problem (I think..). We just wouldn't put her down to quietly settle to sleep- we rocked her, picked her up endlessly, carried her, fed her to no end- it went on and on. I was so worried about her lack of sleep, brain development etc etc and I realise now that she needed peace and quiet. Perhaps you could hire a baby hammock to try for a couple of weeks?