It's odd that no one has analyzed the 433 MHz band to find out what is interfering with all these signals. It's most likely to be a bit of misbehaving equipment permanently on a channel.
Presumably they've given Ofcom a call and they'll go look whenever they get around to it, but some noise on ISM is probably not treated as an emergency.
If you look at the Ofcom schedule it says that 433Mhz ISM devices must accept harmful interference. So you’re probably right. They aren’t safety critical systems.