2 very good questions. I was just expressing the positive - it's a big step forward even to have a candidate that fits the symptoms this well. The vibration is the same intensity, I feel it through my feet the whole way between where I live and the office block, it operates 24 hrs a day at least 6 days a week and if I can definitely connect a time the aircon units are off to a time I'm feeling no vibration then I've proved it 98% to my satisfaction.
The down sides are that few other people seem to feel this, even close neighbours to the office and proving it to my satisfaction as you say doesn't stop the problem. However, it seems likely that there are some others who are bothered by this and if I can find them that's a step forward. Then there's the possibility that they are breaching industrial regs - I've never felt anything like this before - so making an official complaint might start something. Lots of ifs but at least there are ifs to check. If you see what I mean

. But whatever is ahead, finding something that fits the symptoms as well as this seems to is a win. And I'll take what I can.
I have to say that today so far has been good. I slept from about 5 am to 1 pm and it wasn't vibration that woke me. I've felt a little since then but way down on where it's been recently.
There's also the fact that having sorted the issue(s) with my neighbour has allowed this step forward: before he moved his computer or whatever it was and perhaps sorted his boiler issues I couldn't identify THIS issue as a separate issue. All I can really go on is a directional sense. Even strength isn't much help - it only gets clearly stronger through my feet when I'm within 100m or so of the office and the directional sense said a lot was coming from my neighbour before and it didn't after he made changes. And of course the strength in the overall issue of vibration halved (or thereabouts). That's what's pushed me to look further afield than I had been.
edit: For some time I've been thinking this is something smallish quite close - or big further off. There have been several candidates for small and close including the pub and the microbrewery but (fortunately) none fit the symptoms very well. Timings were not close enough. But having eliminated small and close I have found big and further away.