DD is soon to go to France for 3 weeks with he school. Staying in the school lodge
She will be doing some skiing amongst other winter sports.
School (independent) have said she is coverd by the school insurance except for medical cover which is coverd by her EHIC card.
Feel a bit uneasy about this. Lots of "what ifs?" going around my head. IE: what if the worse happens and she needs to spend weeks in hospital to flown back by air ambulance etc.
She also has pre ex medical condition (renal) fully under control and reviewed annually at hospital, as well as asthma which is controlled by inhalers - never had an attack.
Can I take out a policy for a single trip, under 18yo travelling with the school with hazardous sports added and pre ex med conditions declared? Or can cover only be taken out on an adults or family policy? 
Really quite pissed off that until I emailed school today there has been absolutely no mention of insurance and am still left feeling very vague as to what the school insurance will cover in the event of something awful happening. The school is currently on half term and getting hold of anyone at shool is not easy this week. DD leaves for her trip on Sunday.
Can anyone advise please?