I read this screenplay of the film, as my dad brought it over at Christmas and informed me it was one of his favourite films. Not everyone's, as mine is the first rating and there is no book cover artwork! I enjoyed it, and Clement and La Frenais were two of the greatest British comedy writers ever.
What I did find interesting was how much of the emotions of the characters they gave away in the directions. Neither of them directed the film, and maybe that had something to do with it. Normally there is a sparsity in direction in a screenplay, they told you on several occasions what the characters were thinking, instead of the usual one word to help.
This would be an interesting read for someone studying film/screen writing, probably to be told by a lecturer 'less is more!' and 'leave that for the director to decide.'