thanks girls some awesome advice here. i thought about an extra booster after i posted this lol
i will do a strip wash and add a booster and see how i go.
they get washed with her singlets & things that are hardly dirty with about 1/4 scoop of powder and nothing else so i think thats relatively close to the recommendation but there could still be some build up. i might also try a few different brands just buy 1 here and there to see if a side closing one is better, try some that arent aio etc etc
shes in the bbh large skye and from memory thats their biggest

thanks again for the advice much appreciated