Just finished Happy Valley on Prime (maybe Brit Box) and really enjoy it!
Since it first aired in 2014 and finished in 2023, I thought we were going to keep busy for while - but it is only 3 seasons! There is a 6-year gap between seasons 2 and 3. The creator specifically wanted time for a character to grow older and apparently was kept busy with other projects. Amazingly, she was able to get all the actors back!