I think what you mean is that you are just about to start Working Trials, you have to qualify CD first before going on to the other stakes (in championship anyway)!
There have been Giant Schnauzers worked here as Police Dogs and several compete on the continent in Schutzhund, Mondio etc. However the breeding in the UK generally produces a different type of dog.
Irish Wolfhounds and Great Danes to name but two giant breeds have qualified in Working Trials over the 6ft scale.
A miniature schnauzer had qualified in Working Trials and I seem to remember a standard years ago.Β Not sure they would be up to the manwork in the UK though!