Juergen Hannappel writes:

I'm not aware of any laws in the UK that restrict saw arbor length.
There's certainly no ban on the sale of dado saws. I wouldn't

AFAIK wobble dados are forbidden.

Well, hell, that even makes sense, but has zip to do with safety. They're nasty
tools, hard to adjust, leaving a V shaped groove bottom, and they sound awful.

Now, ask me how I feel about wobble dado sets.

Charlie Self
"If a politician found he had cannibals among his constituents, he would
promise them missionaries for dinner." H. L. Mencken