you could go for hobbywing xerun esc 60a-sd. you can get it from giant shark for £60. other servo choice is savox 1251mg.
i bought the lipo shorty battery from hobbyking.com
http://www.hobbyking.com/hobbyking/s...APPROVED_.html
or you can use any "shorty" Lipo pack. I am not sure if saddle pack will fit in.