Thank you so much for the recommendation. My DS3 is currently confidently reading orange level books and these are just the right level for him to read. Mr Tick the Teacher arrived today and he read it to me this evening and really enjoyed it. He's decided more books in the series would be good as rewards when he behaves well (we've had issues with him getting ready for school and bed and have had discussions about more appropriate behaviour) - I'm always happy to buy books and if he actively wants to earn them then even better :D
Mrs Vole the Vet is next on our list :D