Hello all,
As someone who spent 20 years on and off on building sites I would never claim to have seen it all - but I can offer my few pennies, and perhaps save us some in the process 
I have used professional tools and thankfully by the time approaching £1k has been spent they are usually a joy to work with. Alas, even the very tough ones can be misused, and the service/spare charges can be brutal!
When I set up my own business I could not justify a high-end tool, so I had to get creative. The result that has served me very well with all kinds of hoovering of dry matter is a hack I would propose to you - I don’t have any photos of my rig as it is on a site in Walthamstow (I am the nicest builder I have ever met, the clients live back in their house but I lent them the beast…).
I looked for the cheapest vacuum recommended on some builders forums, and found this one:
advantages: has a bag, but can be used without. Has a filter which is not cheap, but washable. I bought a spare filter, and every Friday after leaving site I would take one home and use the garden hose to clean it properly. Both filters have been with me for a couple of years and show hardly any wear.
The trick: Very little dust ever enters the vacuum cleaner. Because two more items get grafted onto it - a vortex separator:
mated tightly with any old bin, as long as it is properly air-tight:
and to hook it all up a length of cheap hose and some good quality gaffa tape and…
Well, I had my doubts. But I have seen good quality vacuum cleaners die of clogging and overheating ten minutes after they met fine red stone dust. And this combination… it lasts. And it, erm, really sucks!
Fine dust will clog up the final filter after a few hours - but by that time the blue bucket has already been emptied two or three times, and the Metabo only has a smattering of stuff in it’s own collector. And that’s when you swap the filter, and all is as new.
Some folks have lashed this combo onto a trolley, i.e.
http://s3.amazonaws.com/finewoodworking.s3.tauntoncloud.com/app/uploads/2016/09/06051623/Resize_of_Re-exposure_of_IMG_1682.JPG or even quite posh: https://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fwww.makermasters.com%2Fwp-content%2Fuploads%2F2012%2F04%2FS19900081.jpg&imgrefurl=http%3A%2F%2Fwww.makermasters.com%2Fdiy-cnc-project-dust-deputy-cyclone-separator-cart&docid=RE4_P4wEPs7IuM&tbnid=tTxR25OOWTcvXM%3A&vet=10ahUKEwjakvrnvtzWAhViF8AKHe1tCyQQMwgvKAkwCQ..i&w=1200&h=1600&bih=759&biw=1436&q="dust%20deputy"%20bucket%20vacuum&ved=0ahUKEwjakvrnvtzWAhViF8AKHe1tCyQQMwgvKAkwCQ&iact=mrc&uact=8
I would happily offer to build a system like that for the space if you get the parts (which of course do not need to come from Amazon, the filters for my Metabo came from a specialist cheap reseller).
If on the other hand you want to buy a Festool or three, I would not refuse to use those 
As an aside, using a pre-separator is still a good idea for professional tools. Especially when vacuuming around metal workshops, it’s nice not to have sharp bits rattling around your expensive hardware - the vortex separators are incredibly efficient, and the buckets are nice to carry out and tip out!
Toodles,
Hanry (not the vacuum! But they’re ok too!)