£550 is actually rather cheap, and if you add EU legs (for instance), it may well be that the additional cost of getting to/from somewhere else will push the total cost well above that.

Bearing in mind that dropping a leg mid-trip will not be an option at all (the whole itinerary is likely to end up being cancelled), so it may just end up not being worthwhile (both in terms of time and money) to try to fly to somewhere in the EU and then back to the UK.

Additionally, being winter and around Christmas, irrops may affect your daughter much more badly due to shortage of seats around that period (e.g. having to wait for a couple of days to find seat availability after a misconnect/cancellation).

In addition, there are various other indirect routing without doing a "reverse ex-EU", e.g. flying on LH etc, but the same winter risk applies.

If it saves a couple of thousand Pounds, then it may be worth the but I would certainly not try to save a couple of hundred Pounds from £550 (not that I think it's likely to save anything like that from this fare) by peculiar routing in winter. Flying direct is the way to go unless indirect routing saves a substantial amount of money.

If you feel that £550 is too expensive, you might like to check out the fares on NH as well. JL operate JBA with BA so it may be the same fare but still may be worth having a look.