Thanks Taurean. We have tried the 'tough love' thing and TBH, it has made things worse. I think that is the reason that I cannot leave the room without her launching into hysterical screaming. We shut the door for about 8 nights and she screamed for hours at a time, trashed her room completely, crawled into bed from exhaustion and slept for about an hour and then started up again until morning. She will settle quite quickly if I sit with her (but not DH) but I can't leave the room so that isn't really working for me.

Thanks Olive, I might try the Rescue Remedy first since I can get it here.