No we are on the same page apologies i misunderstood you. I think what you are suggesting is exactly what i'm looking for. I can set default values for both variables as spaces in the class and throw an exception if either has a value of spaces when the class is called. If I pass in the variables when calling the class this will override the default values set in the class.

Next question - is throwing an exception in a constructor method bad practice as it leaves a half instantiated object?

Many Thanks.