I phoned up today to arrange a visit tomorrow morning to sort this mess, but custard said he has had a go with his jet washer and it's not shifting.
It's concrete with a gloss coating on it He says, I don't know what that means but I hope it's not too expensive to sort, I can't afford this but have to sort out for them.
I think our drive is like that. A sort of fake block pattern marked out on concrete, coloured and then a shiny coat.
I'd hope the 'gloss' coating would help a bit and reduce the sticking power of the Bonding maybe.
If it's in blobs, then maybe a wallpaper scraper or something like that may help.
I use the little abrasive green pads to get stuck Bonding out of buckets, and works well. (edit: with lots of water too!)
Tho should you need to resort to scraping or abrasive stuff.... I have found a concrete drive like this can be prone to chipping on the corners of the block pattern.
When we had to clear the snow last year, I managed to chip it in a few places when using the spade. Just a warning.
Good luck.