Horses for courses? I am not too sure about that site anymore.
The job I am on this week is a bricklayers dream. Labrokes bookies next door and the Red Lion across the road. After a quick couple of pints at lunch we made in time for the 2.30 at Huntington. Amazing Valour looked good at 4 to 1 and was a Course and Distance winner. I stuck a tenner on and the donkey didn't even get in the frame.
About your bricks, I did build a brick circle in the garden of our old house using ordinary facing bricks and they were fine, and I have used ordinary bricks on our kitchen pantry floor.
It really depends on the amount and weight of traffic going over it and also on the ground and weather conditions. If you want to take a chance on using them and DIY at least if they go wrong in time you havn't lost out in labour charges.
BTW the bricks were laid on a hardcore/concrete/mortar bed.