50% of my work is as Expert Witness for various local authority Trading Standards and Police forces around London and the southeast and I have come across this problem several times. The initial scam is the selling of the spray foam application possibly done a couple of years ago but is still an ongoing problem. The second stage is then the removal, often by the same gang, stating that the foam is dangerous and since Grenfell Tower has been banned! I have also noticed that in all the cases I have seen including one only a few months ago, the elderly property owner has had the insulation topped up to 250/270mm under the Warm Front scheme back in 2010/ 2012.
It is known that most of the disreputable companies seem to be based in Dorset with Bournemouth being a hot spot at one time. They are not only selling spray foam but also PV panels and solar heating etc. I believe National Trading Standards are proactive on this but unfortunately I don’t have any contact with Dorset Council Trading Standards.
I would suggest that you advise your clients to contact Citizens Advice as this is the only way that Trading Standards can be contacted as there is no direct phone link. They need to explain that they feel they have been scammed, that their consumer rights were infringed and that damage has been caused to the roof which has been confirmed by a Surveyor. They need to ensure that the call is logged on the system and they get a reference number. They might get a call back from their Local Council Trading Standards or Dorset if that is where the trader is based. There might be an ongoing investigation and their complaint may assist with that case. Alternatively there may be one or two previous complaints about a company but no case has as yet been looked at and their complaint may tip the balance as I think the magic number in some instances is 3 complaints but the more the better.