By roughcast do you mean it has stones/pebbles in it, or is it just like Tyrolean render?
How much has broken away?
Have you painted the existing rendering?
If so, I would DIY!
Get a bag or two of tryolean render, read the bag, clean the area removing loose render, apply, leave to dry, then paint.
Jobs a good un.
As far as quotes are concerned I can't help you.