Without seeing it and having a good poke around, not really any way to say how much it is worth, but as said, not that much. MOT history isn't great, but it isn't terrible either, looks like there is an issue with rust around the rear axle mountings. Fortunately the MOT is valid till January, so not strictly necessary to deal with that if you just want a quick sale.

You definitely need the battery charged up, it may be the case that having someone take the car out for a decent run will suffice, and it sounds like it is badly needed anyway.

For getting it sold, I'd suggest We Buy Any Car or similar, especially if you want a quick sale.

Edited by badbusdriver on 01/09/2021 at 17:48

Sounds like the K11 model problems (my old car built 1996) - significant underbody corrosion - were still there in the later K12 model the OP owns.

I palmed my car off to Motorpoint when I bought my Mazda3 from them in early 2006 and I got £450 PX for it - and that was with only one MOT advisory (corroding crossmember) after I'd had some rotted through bodywork replaced to get it to pass. After the costs for that and the service, I had about £100 leftover. I didn't bother getting thatcrossmember fixed fopr the same reason - I'd be out of pocket.

With that many advisories/minor items on the last MOT pass after getting three major issues repaired, I agree that the OP won't get that much for it, especially given what car (and specific sub-model) it is, even with second hand prices generally at an all time high due to the new stock problems associated with the pandemic.

If the car has been standing around for a few weeks, then I suspect the battery is flat . That’s why the locking isn’t working . As for the value of the car , I would say not a lot . Looking at the mot history, it would appear the car is suffering ongoing chassis corrosion , which makes these an uneconomic repair.

Get a friend or relative to try starting the car with jumper leads off their own car. Once it is going it needs a good run and that may be enough to charge the battery. Start it up and run it for a while at least once every couple of weeks. It isn't good for a car to leave it standing idle.