Perhaps you could have some sort of prologue that introduces him at the very beginning. Or, you could have him puttering around in the background, casually mentioned but never named. Major characters not introduced until much later? Your Freshman Comp teacher would be appalled!

Also, I want to see pure Aristotelian unities on this one! Sure, this might be a bit limiting, but I foresee a great British farce with lots of door openings and closings.