I've had recent dealings with (name deleted), we got a large area laid with London Cobble effect. We were extremely disappointed with the results, most of the "cobbles" in one very large area looked as if they were crumbling away - it looked to me as if the concrete was possibly a little dry when the mats were applied.
We were told by (name deleted)(afterwards!) that this sometimes happened, and that it was "bad luck" that it happened to us! I don't think so!
As he was not able to guarantee that removing & relaying would produce anything better, we said we weren't happy, and it was agreed that he would take it away. To cut a (very) long story short, however, we've had to pay for the removal, as otherwise they "wouldn't be responsible" for any damage to underground pipes or the house during the removal process. Blatent threat.