It would have to be Admiral - the most obnoxious insurance company bar none.
My policy (with them - never again) provides the following in the event of a claim: Repair of my car (costs them) and courtesy car (costs them)
both provided at no extra costs to me in the event I drive into a wall.
But - my car has been in dealer. Dealer lends me a car but I have to insure it - fair enough. I call Admiral and have to pay £24 for the cover for a week. This is not an admin fee according to Admiral - it's to cover the "additional risk". I contest because (a) I can only drive one car at a time and (b) if my car fell off a ramp at the dealers, would Admiral pay out? I think not.
I then have to extend the cover for another week (contiguous, no gap). They charge me a further £24.
I made my views very (very) clear to them & as a "goodwill gesture" they credited the second charge.
All insurance companies (including warranty companies) are a combination liars, cheats, thieves to some degree or other, but Admiral are top of the charts in my book and to charge more for for a SAC is a step too far if the police do not class it as a conviction