A belated appreciation of this excellent puzzle. What an impressive piece of grid construction and, more importantly, it was fun to solve.
I'd become so fed up with Harribobs's recent run of count-around-the-grid puzzles that I nearly skipped this. It was thanks to the recommendations on here that I did it today. Let's hope HB's future puzzles will be in this vein.
I really MUST pay a trip to the stationer and get some coloured pencils...