Hi Kay.
I hate to be the bearer of bad news but no. The guys that done the repairs should have tried to color match the existing, rather than ask you what the spar stone was called.
Because the spar or pebbledash as you call it is fragile, you can't do much to it, apart from paint it, which will take huge amounts of paint. There is no way to clean it either as you know by now that even the rain make it fall off.
There is only one way to a close match. Do some test mixes of cement with colorant to get the right amount of shade, this is best done by measuring the dose's of each part, sandlime, cement, color. This will take a few days to get close as you need to let each batch dry out.
Then take a yard brush and gentle brush a very large area of your house to collect the loose stones. Then the repair can be done again correctly colour matched.
Hope this helped.
Joe Dybowski
www.simplybuildbetter.co.uk
Joe Dybowski, May 2009
