You reminded me about this UBI pilot project which was reported in the media just about two years ago (also, I found critiques of the idea here - pros and cons, here - the dystopian truth and further discussion here - "money for nothing?". I haven't been able to find any follow-up of this pilot, although it looks like there is another proposal for a pilot in Manchester. I'll keep looking, maybe @revisesociology has come across something?
I like your idea about using UBI as a transitional arrangement for industries/companies which require re-structuring or even exiting. There was an article yesterday about the declining middle-ground market for bread. Two of the biggest companies have been operating at a loss for a while and are discussing a merger (Crumbs! How Britain fell out of love with the sliced loaf). UBI may be able to help with the restructuring involved in these kinds of situations.
I think there would be other savings as well: improved well-being would lead to lower costs in the NHS, both mental health services and the reducing the prevalence of long-term conditions, and social care. Some of the bigger local authorities here have been looking at moving some of their budgets from social care into economic development as creating secure income (however that is done) would decrease demand for benefits and services.
Great discussion topic, it's helped me with some things I'm thinking about at work, in fact, I came up with a proposal this morning as a consequence of thinking about your post (I may have got there eventually anyway, but much more slowly) 😂.