Re: Hah! New keyboard required!
Our external is pebbledash too (or a close relative). Feel very carefully for the drill exiting the block and entering the 25mm or so of render which holds the pebbledash, and take it very slowly from there, but you will still end up with a bit of a spall rather than a neat 8mm hole.
Larger holes - where you have to use a core drill (I've done a lot of pipework recently) - are much easier in this regard because you can keep drilling until the pilot dril pokes through (use a "spotter" if necessary - small children with loud voices or PMR radios are ideal) and then finish the hole from outside in. It doesn't matter if the pilot spalls as you're cutting that bit out, and just doing the last 25mm or so from up a ladder isn't so bad.
It's also amazing what kind of damage can be covered up with a bit of the correct colour paint.
Note that Sky installers have long since given up on making neat holes, and use this sort of thing to cover up their mess - until the silicone they use to glue them on fails, anyway.
M.
Biting the hand that feeds IT
