You'd never prove ('beyond reasonable doubt') that it was 'criminal damage' [as defined by the Criminal Damage Act 1971]. To do so it would be necessary to prove that either 'intent' or 'recklessness' was involved. While a civil court (where only 'the balance of probabilities' needs to be considered) might accept that there was an element of recklessness involved, a criminal court almost certainly wouldn't.
I used to supervise the delivery of Yellow Pages across much of East Anglia and our delivery teams usually managed to break several letterboxes with each new edition. (Indeed, I've been accused of breaking quite a few myself while delivering both Yellow Page and Phone Books, often when it was obvious that the damage had been done months beforehand. I admit to breaking about half a dozen, over several years, though!). The delivery company (Deya Ltd) was usually reasonably quick to pay out though.
It would be unusual for a firm of home cleaning operatives to employ their own delivery staff. It's far more likely that they'd use a dedicated delivery service, so it's that firm which you'd need to track down.