Thank you all!
She is already taking magnesium supplements although haven't tried it topically. We have tried all the usual things - rescue remedy, various essential oils, warm baths, white noise, fidget toys, calming music, weighted blankets etc.
So all the above keeps the anxiety at bay fairly well during the day but problem is that she still has flashbacks to past events at night when trying to get to sleep!
She is working with a counsellor and is hopefully making some headway. The counsellor uses a Sensate (vagus nerve stimulator) during the sessions and that was where my DD got the idea for the CalmCarry as she felt the Sensate worked and wondered if it was similar . But the Sensate is closer to £300 rather than the £50 for the CalmCarry!!!