If true I’m very surprised the UKSchwab govt doesn’t regulate woodstoves as tightly as guns. Personal resourcefulness is not a quality the ruling class likes to encourage.
It regulates them pretty highly, although not as tightly as firearms. There have been a couple of strict limits placed on particulate emissions. The first one was rather easily met; the second is tougher, and some manufacturers have had to use catalytic inserts to meet them.
Personally, I detest catalytic inserts, because they clog, they are non-standard, and they only work well for the part of the burn that is both hot and producing a lot of VOCs.
I was fortunate enough to upgrade my stove in 2019, when the first set of regulations was in effect, but not the second. The burn (which is much cleaner than any stove I've had in the past, but still leaves creosote over the course of a winter) was improved by the creation of secondary air paths over the top of the flame.