I volunteer my amateur enthusiasm to whoever works on this.

One thing I'm curious is what percentage of worlds would require the bunker to be well-hidden in order to be useful, e.g. due to an all-out WW3 where there are automated weapons seeking out targets that would include bunkers. I am less sure the size of the risk of Local Warlords In Your Area, though will note that if it's near a local population the bunker should be cooperative with nearby inhabitants rather than engage in the false individualist bias that is rampant in survivalist thought.

I think it would make sense to have multiple bunkers distributed in different geographies and suited for different GCRs, where some fraction of these bunkers are kept very very secret. But I strongly don't think a v1 (Version 1 / Vault 1) should have that feature.

Quick note that I misread "refuges" as "refugees," and got really confused. In case anyone else made the same mistake, this post is talking about bunkers, not immigrants ;)

I suspect this is down the road, but when it comes down to site selection, I follow the Eastern Ontario/Western Quebec (Canada) real estate market. This region has the benefits of political stability, fresh water, and relatively easy access, however getting permits to build geothermal and massive scale projects would be difficult as building, especially close to water, is quite regulated. There are 100+ acre properties like this one on a deep lake: https://www.realtor.ca/real-estate/24040099/950-ch-assad-lange-gardien which are coming up for sale as people realize their bush land/farm is valuable. You could buy up land like this for future use.

Bunker on island is probably a robust set-up, at least two given volcanic nature of eg Iceland, New Zealand: https://adaptresearchwriting.com/island-refuges/ Synergies/complementarities in island and bunker work should be explored. We're currently exploring the islands/nuclear winter strand (EA LTFF), and have put in for FTX too. 

Many have observed that Elon Musk's Boring Company (which ostensibly is about improving the tunnel-digging state-of-the-art so that we can have lots of nice subway / tunnel infrastructure and alleviate traffic) seems like it would be quite helpful for digging airtight underground habitats on Mars, thus tying into Elon's SpaceX ambitions of settling the red planet.

Similarly, I feel that the project of constructing  really-high-quality civilizational refuges could benefit from the technology required to build space habitats like the ISS.  As excerpted from a longer Forum comment of mine about the overlaps between EA & space exploration:

I think the bunker project has a lot of overlap with existing knowledge about how to build life-support systems for space stations, and with near-future projects to create large underground moonbases and mars cities.  It would certainly be worth trying to hire some human-spaceflight engineers to consult on a future EA bunker project.  I even have a crazy vision that you might be able to turn a profit on a properly-designed bunker-digging business — attracting ambitious employees with the long-term SpaceX-style hype that you’re working on technology to eventually build underground Martian cities, and earning near-term money by selling high-quality bunkers to governments and eccentric billionaires.

Is not the greatest refuge what Elon is planning for Mars? That's a separate track though we should be working to expedite and ensure that that civilizational plan b is operational ASAP. 

Does the CEO have to be based in the UK or is willingness to travel a lot sufficient?