The older he gets, the more obvious it becomes that Monty is not at all a pure-bred Lab'.
He's a big lad, and looking through my Boy Scout's Book of Dogs suggests that his mother might have become friendly with a Ridgeback.
His overall appearance is still that of a Lab', but he no longer has that dewy eyed 'butter wouldn't melt' look that is so popular with bog-roll manufacturers.
I understand that one can send off hair samples to some mad-scientist laboratory in Switzerland, and for several thousand quid they'll tell you exactly what mixed-up variety of dog you possess. Maybe Lady Magnon would enjoy an unusual Christmas present this year!