Lady seems to be doing absolutely great on Re-Leve, she has actually started to put a little bit of weight back on!  She gets 1kg 3x daily, with chaff, and I have kept her on a cup of linseed 2x daily too.
Most incredibly, her temperament is DRAMATICALLY different! She's still just as keen to work as ever, but her concentration levels are a million times better.  She's been much better to work at home and has in the past 2 consecutive weekends jumped her first double clear (she wasn't so strong and much more responsive when I suggested it was not appropriate to gallop at the second part of the double) and even more miraculously- had a placing at unaffiliated dressage in quite a spooky arena.  I don't actually even normally take her to do dressage on its own as its quite embarrassing- she's interested in anything else that might be happening, and throws her head around to see it, or calls to any other horse in the vicinity!
I'll be taking her XC schooling in the next few weeks, so will just have to check with the new found attention and control that she has enough energy to event.
Thanks very much for all your advice - she will definitely be staying on Re-Leve!

Lady - January 2016