you're right about M1 missiles availability - i never paid much attention to it as i haven't bought into the whole idea of Russia sending that one BUK. I'm not even sure why such an emphasis on it - for example I still remember my frustration with Russia that they'd allow the rebels to be pounded from the air and wouldn't send them capable anti-aircraft weapons (it didn't even cross my mind back then that civilians would still be allowed to fly over the war zone especially given the use of military aviation - i mean that would be beyond stupid, wouldn't it? yet here we're...)

Anyway, giving the state of shock the catastrophe put everybody into and its huge political ramifications, no evidence produced after the catastrophe can be trusted without good cross-check verification. Everybody was lying, altering and producing fake evidence after the catastrophe. There is no need to even try to discuss Russian "photos" of Ukranian SU-25 shooting MH-17 with something looking like Star Wars laser canon. The rebels deleted tweets and posts made in the half-hour after MH17 where they were celebrating shooting down of another Ukraine military cargo plane. On the other side things weren't much better. Immediately after MH17 went down, Ukraine government produced that famous wiretap of cell phone conversation between a leader of rebels and his Moscow handler where the rebel reported about discovery that the shot down plane was a civilian plane and that the plane was shot down by the "cossaks from Chernuhino roadblock". Chernuhino is 70km+ from the firing position specified in the Dutch report. So either Dutch are lying (why would they?) or the Ukraine government falsified the evidence. For the couple weeks before July 17 Ukraine was deploying the Buks all around the warzone - the on duty systems were reported on Ukranian state TV with the military leaders of the Ukranian "Anti-Terrorist Operation" talking in front of them, and the Ukranian journalists published photos of deployed Buks from the ATO zone, not counting multiple pre-July 17 social posts related to those deployment. Well, next day after MH17, on July 18, Ukraine clearly stated that no Buks were deployed before July 17 in the ATO zone, only MANPADs.

So, the only evidence that can reasonably be taken into account is the one that was published before the downing of MH17 (i don't know about any evidence published after the shot down that has been cross-verified).

So, this is what we have as evidence from the pre-MH17:

1. At least 2 Ukranian bases with Buks - the bases A1402 and A0194 of the 156th anti-aircraft regiment were captured by rebels before July 17. At least one launcher, on A1402, fell into the rebels hands. My comment here: military hardware is repaired by replacing modules. Ie. it is pretty easy - go to the storage, pick the module and replace. Engine, etc. is easy too. Definitely repairs could have been carried out between June 29 (the capture, actually June 27/28) and the July 16 when the Ukranian SU-25 was shot down between 6 and 8 km altitude near Amvrosievka.

2. A Buk launcher on low-ride trailer was seen around 9am July 17 in Donetsk. It was accompanied by gray RAV4, Russian made SUV and mini-van. Those cars were seen in a convoy of several tanks, etc. on July 15/16 that was going to and coming into Donetsk from direction of Enakievo, and the convoy may have been from Russia. That convoy didn't had Buk. My comment: bellingcat considers that it is the evidence that Buk came from Russia, ie. it was going separately from that convoy. I think it is completely opposite - you wouldn't let your extremely important asset to separate from convoy, especially on the road that was close to and contested at times with Ukranian forces. The cars - SUVs and minivan may have been carrying related rebel commanders/coordinators and the crew for the Buk. There is no evidence connecting that Buk in anyway to all those Russian Buks across the border.

3. MH17 was shot down by Buk from a position, according to the Dutch report, south of the road between Torez and Snezhnoe.

That is basically all the evidence that is known. All the rest of the stuff - given for example how fast Ukraine produced the [falsified if you believe Dutch findings] wiretap which i listened to on California morning of July 17 - could have been easily falsified.

So thus it all comes to interpretation.