Yeah same, never used warranty companies because there's always a catch! £500 per claim seems to be the catch here. Other catches include things like excluding failures resulting from track days, excluding wear and tear + some other stuff. An exhaust, clutch or chain job will easily eat that 50 sheets, and more. And if you need a new turbo, it'll cover less than half of it, just for the part.
If we had proper "bumper to bumper" no quibble warranties like they have in America, I'd probably do it.