All conspiracy theorists take a step back from their keyboard
Here's the TL;DR on this:
1. Sensyne (Drayson) wanted to work on AI stuff for the medical sector. So far, so good.
2. OUH NHS trust and GOSH both were interested in this (because a) Oxford is always interested in advances in science and b) GOSH is always trying to make pediatric medical things better for their ultimate charges, the kids). So far, so good.
3. Sensyne says "we'll need some funding to do this, and we'll need data to train the AI" (note the mentions of a 'funding round'). OUH and GOSH go "we have data, but it'll cost ya". Sensyne points at the "we'll need money" statement. OUH and GOSH say "well, if you give us shares, you can have the data" (or maybe Sensyne said "we'll give you shares if you give us the data" - the end result is the same). So far, so good, because both trusts have a decent history where this is concerned.
4. Sensyne fails in their quest (or appears to fail in their quest, or is burning money left right and centre in the quest). They get delisted. They're *not* dead, but the shares are practically worthless.
5. OUH and GOSH write off this 'investment' they obtained by bartering data for shares.
6. Sensyne is *NOT DEAD*. It's *shares* are flatlining and it's been delisted, but the company hasn't gone into administration or gone bankrupt. They *DO* still have the data.
7. Yes, OUH and GOSH *have* lost money. The investment they got was in exchange for data. They should've gotten cold hard cash for it, they didn't. They took a stab at what could've, if Sensyne's quest had delivered a great result, turned into quite a good cash return (especially if Sensyne had gone and then sold itself to someone big). But, they failed, they haven't sold themselves, their shares are worthless, and thus OUH and GOSH's grand idea *also* failed.
8. GOSH and OUH *could* buy it back, and throw more good money after bad (but get their data back). They could buy Sensyne, terminate it, and get their data back. Either way, they would be throwing more money away, *actual* money, not "here's some imaginary value that needs to sit in an accounting column somewhere" money. No public money has gone anywhere (unless this point happens).