Sorry to hear your selling up.
Here's a price tracker you may want to look at:
http://www.toytracker.net/giant/trac...ant.html/busts
But may also be a good idea to have a look at recent completed listings on ebay, at the end of the day it's down to what some one is willing to pay at that time.
Here's my thoughts, prices exclude shipping, some of the busts below can still be obtained from some retailers for the same price as yours or below.
Grevious £40
(£30-£40)
Maul £40
(£25-£35)
Paplatine £60
(£45-£60)
Clone commander 5 pack. £500 Inc Postage (totally complete including shipping box)
(£350-£400)
Clone Sergeant AOTC (Green) £90 Inc Postage
(£70-£75)
501st Clone £40
(£30-£35)
Senate Guard £40
(£30)
Scout Trooper £60
(£45-£60)
Tarkin £60
(£45-£55)
Chrome Stromtrooper £45
(£35-£40)
Royal Guard £40
(£20)
Luke Skywalker X-Wing Pilot £45
(£35-£45)
Han Solo £35
(£20-£30)
Princess Leia £35
(£30)
Bossk £45
(£40-£45)
Dengar £30
(£25)
Zuckuss £30
(£25)
Qui Gon Jinn £30
(£25)
Obi-Wan Kenobi (Ben Kenobi ANH) £30
Yoda ESB £25
(£20-£25)
Gamorean Guard £55
(£45-£55)
Greedo £55
(£40-£55)
Lando Skiff Guard £40
(£30)
GG Busts in general do not seem be selling as high as they have been, although I was quite suprised to see a Leia / Boushh sell for more than £50 the other day.
It a buyers market at the moment unless you can wait a while, it's a good time to fill holes in your collection (the other lines your now looking at).
I've be collecting a few extra Clone Troopers to customise at some stage & some Yoda's as my little one loves them.
Hope you manage to sell for the prices you want, I'll be keeping eye on Yoda