[Closed] How much to repair damaged render?

The man that came round to put a "For Sale" board up on my house has managed to crack off a rectangular piece of render at the bottom (about 3x9 inches) by wedging the post against the wall and letting it twist in the wind.

It's still stuck to the wall at the moment, but moves under pressure and will presumably fall off at some point in the near future. How do you repair this? Presumably getting a colour match is the hard bit, then you fill in the hole?

Not particularly bothered about cost since the estate agent will have insurance but ball park figures would be interesting, not least because I can get them to knock it off their final bill.