Hey - That is a lovely little collection.
In terms of getting best bang for your buck - sell individually, no question.
Bulk sales tend to be the domain of dealers (especially for a lot like this) and since they buy to sell, they will likely look for a 3x return on their investment, which means they are likely to only offer you a third of what they can get for it.
You might find a private buyer who is happy to make a better offer.
You could try auction houses like Vectis, they would sell these easily enough, but again, they take a cut - but other than getting the items to them, you don't have to deal with anyone or anything after that.
Listing here is a good option and there are Facebook pages (never use them myself). There is also Ebay, but with new sellers rules and so on, I personally won't use them to sell anymore - but they are an option and obviously have the biggest customer base.
Depending on where you are in the country you might find a comic store or vintage toy store that will sell for you, for a percentage of course
As for valuations, overall I would say your stuff should be (or looks like) it is at the top end of the loose/complete with boxes and extras end of the scale, everything looks clean and good.
Snowspeeder: £80-£100
AT-AT: £200ish if the chin-guns are there - £140ish if they not
Jabba: (Bit more of a guess here) £150ish
AT-ST: £120ish
ISP-6 - Quite a range but I think £60/£70 maybe
X-Wing: £150
Falcon: This one looks to be missing bits (Radar Dish, Training Ball, Ramp Struts) and is maybe yellowing a bit more than anything else - But If complete you're looking at £150+ in that condition, Non-complete a fair bit less.
Rebel Transport: If complete maybe £100ish (maybe more if all the figure accessories are there (the backpacks and the breathing masks are in the picture with the figures, so they are there) - and both top parts of the ship - only one in picture)
Figures: A few really nice looking figures there, the most valuable are the early ones and a lot of the value is in them with their correct weapons etc. The Han Smuggler and Princess Leia complete go for good money, Leia £100+, Iv'e seen Han go the same, but I would say a little less £80ish - The solid R2 looks in amazing condition, easily £50+ for him (he's great). The Death Star droid seems to be enjoying a moment, so could be £30ish there and if the Boba Fett is in good nick with the gun he can go for the same, maybe a little more. Overall the rest of the figures are probably anything from £15-£20 each (with some wiggle room) if complete - again a lot less if not.
At the end of the day - something is only worth what someone is willing to pay for it, but you have some nice items here. Others might weigh in, always good to get a range of estimates before setting a price.
Good luck
