I looked into spray foam insulation but not only were there lots of risks, but it was more expensive than traditional warm roof insulation with PIR boards or similar. I do think people should research what they put in their own homes as it wasn't hard to find information that ruled out spray foam insulation fairly quickly.
Having said that, there is clearly some sort of regulatory gap here as not being able to mortgage your home is a very serious consequence of a relatively small and seemingly innocuous home improvement decision.
When I first moved into my house I needed to improve the insulation as the existing stuff wasn't sufficient. I reached out to a spray foam company who sent a salesman around. The guy was incredibly pushy and didn't care about the minor details. When I was saying it was too much he called his manager up on the phone and was talking to her like she was a piece of shit that he'd trodden in. I reached a point and asked him to leave. About 15 minutes after he'd left the manager called me back directly sounding like she'd been crying, asking for feedback on the guy. Even after I said it was a terrible experience she continued to try and sell the service to me! It was probably some terrible double-act to get sales.
It left a bad taste, I got the feeling it was a terrible cowboy operation and they were claiming to be one of the major players in the UK. Seeing this and over time reading people's experiences really makes me feel like I dodged a bullet by not getting foam spray insulation. It all sounded too good to be true.