Has anyone else here read either of the above books?

They're magnificent. I think they're both Edwardian, although Diary of a Nobody may be Victorian. Oh and how could I forget 3 Men in a Boat?

I just love the ridiculous, farcical humour of these books and wondered if anyone could recommend anything similar.

Yes, I loved Diary of a Nobody. I read it years ago and it is on my huge re-read pile.
Have you read Diary of a Somebody by Christopher Matthew? A sort of modern DOAN but written (I think) in the '80s, so even now might be dated. The main character is pompous, humourless and smug. You can't help but feel sorry for him as well. I think Matthew wrote 3 or 4 books about the same character.

Just reading Diary of a Nobody - it is excellent. Can't believe it was written so long ago

I was on the tube the other day and James Fox and son are appearing in a play called 'Dear Lupin'. Interesting.