Very, very few (two to my memory in the last 15 yrs), and both were deemed to have grossly exceeded legitimate self-defence.
What Americans read perhaps is that UK people in such incidents get arrested, which seems backward and unfair, but its police procedure to ‘arrest’ everyone involved for a few hrs until the facts are ascertained, what US media ignores is that the homeowners are released within hrs, after their proof of self defence is established.
As we say on this side of the pond, it is always better to get tried by 12 than carried by 6.