airlines won't generally accept over 32kg for a piece of sports equipment because of manual lifting regulations (they can get sued if an employee hurts their back lifting a 34kg box or bag)
if you need to get bike weight down, dump your tires, tires are cheap in the UK (pair of Maxxis 2 ply is [HTML_REMOVED]#163;45)
watch out for the Da Kine bike bag, its awesome in terms of protection but very heavy and if not careful will push you over the weight limit (I ended up taking my rear coil shock, pedals, seat/post,etc. off and them putting into hand luggage to get the bike bag under 32kg)
my advice would to be get a cardboard bike box from a local store, then you can stuff more into your bike box and bring more stuff home, and the cardboard box will offer good protection if packed right ;)
Mythic / Da Kine / Esher Shore / Freeborn
http://hampsteadbandit.blogspot.com/