Not trying to upset or wind anyone up. I am just saying,look at the breeds origins and what there jobs are. The Greyhounds answer is to chase it. The Bulls is to bite hard and ignore anything coming back.
The Collies is to give it the evil eye.. Im not knocking Collie/greyhound lurchers,Ive had plenty as a kid,but If you are mixing Bull and Greyhound you dont need Collie,as a rule they dont like teeth,and anything else is obtainable from the Bull and Greyhound if the right selection is made..