A nice little lot there nothing to set the world on fire but what you have looks in decent condition.
Value with loose figures is primarily found in the weapons and accessories followed by paint loss and stiffness of limbs.
Vader with saber in tact - £15-£20
Stormie - £5-£13
ERG - £5
Yoda with cardigan - £5-£10
R2 with sensorscope - £8-£15
Bib Fortuna - £7-£12
Klaatu - £5-£8
Weequay - £5-£8
Biker Scout - £3-£5
ATAT Driver - £3-£5
Leia Boussh with weapon - £5-£7
Chief Chirpa - £6-£8
All other £2-£3
Falcon with instructions - £25-£35 (it's missing expensive to replace items like Jedi training ball/arm and the ramp struts but looks nice and clean)
ATST - £20-£25 (looks complete and again nice and clean)
MTV-7 / Speederbike and Taun Taun - £15-£20 (if the Taun Taun reins are intact that could add a bit more value).
Are you looking to sell or hold on to them?