Has had money spent on it - that's impressive and helps with a sale but might not add that much value to the more experienced buyer.
Got a big fat ****ing booklet thing to confirm that. - that's always impressive especially if in strict order of some sort (reverse chronological perhaps) and the whole thing is presented well, better to have loose pages in clear plastic pockets/envelopes. Some with be very impressed if you colour code the booklet to the car and you have separate sections for MoTs and other history.
"Angry" sounding three pot engine - not a description I used - would use - in any advert or description as it sounds like it might be knackered, unless it means something different to younger folk and you only want to sell it to them.
Handles well. Rear beam clamps, soon to have front console bushes polybushed - careful with this as it might suggest you drive the car hard, and there are good bushes and ****-poor bushes available no one knows all the names so I'd leave it at rebushed if you want to include this and leave the potential buyer to ask for more detail if they want.
Something is clunking (WIP) and (WIP) - both you really want sorted before any test drives
Driver's seat padding is a bit poor - that's a shame, you've got the good impression of clean door shuts, driver's or front seats, steering wheel and gear knob make a good impression on a better presented car like yours.
Service history... - you make up for with your extensive big fat booklet, make it a section in that, will look better as a part of something bigger than a slim volume of its own.
You can tone down dents, scratches and key marks with paint and polishes and not presenting the car highly polished like a new car at a dealership, reasonably clean is fine with even a slight layer of dust as this is a used car despite many expecting it to be brand new others will be pleased to see it has all its doors and painted the same colour.
Mild surface rust on rear sills - use something like Kurust to at least stop (slow down) the rust on show, you can then leave it as it is or touch-up paint over, both will show up so you're not hiding anything or pulling a fast one, leave with just Kurust (as with some of the others?).
So if you're a vain and shallow buyer who obsesses over cosmetic ****e, then this is not for you - don't alienate or put off any potential buyers, let them decide the levels and standards they want, if they have objections you can work out then do so, any potential purchaser that is really willing to buy is worth thousands of those that haven't contacted you.
Highlight what's important to the buyer not you, what's important to you may not be to them and the other way round, they may just tell you or you can ask questions or pick up on what they say.
Personally I wouldn't have any personal stuff in the car for the sale photos, (again a clean engine bay and boot deck impresses many, shiny under the wheel arches might be a step too far though. Any car stuff in the photos a buyer may expects and sales can be lost over silly little things particular with something as personal to many/some as a car, if the car mats or anything isn't going with the car don't include them in the photos to avoid confusion. Plus it give you the opportunity if you want to throw such stuff in as a sweetener to swing the sale, silly little things can make as well as break a sale or make up for any other awkwardness. Also remember you are selling the car not buying the buyer, you don't have particularly like them, don't be false but do be courteous, there are two parties to the deal you can walk away from it but so can they.
Oh, no, sorry I've no idea what's it's worth but if you want to sell it I'd suggest you don't hang about and get it advertised as soon and as widely as possible, don't forget locally too, but don't sell to anyone you know and never family as they always want something for nothing and blame you for all the mistreatment they give the car.
Good luck.