Sudden front door issue

Hi Everyone,

Mitch my 5yr old staff has always gruuffed a bit at the front door when someone knocks on it, but recently he has started throwing himself at it and really barking, spinning round etc. I recall him firmly and he listens most of the time but a few times he has growled at me or just carrys on barking > .

tips/help please

Does he have a good quiet command? You could practice by having someone come over repeatadly until he gets used to it and the behaviour goes away.

Has someone been teasing him through the letterbox?

A neighbour's window cleaner used to do that to mine until I caught the ****er.