Pip’s on heat

Pip lives a few doors down from us. She is a young very pretty Irish terrier. This is her first season. Homer is a bit out of sorts and much more vocal. He growled in the most aggressive way I’ve ever head him at a younger male lab on our walk this afternoon. Best he stays on lead a bit more at the moment.
He growled again this morning at a Yong Dalmatian. He doesn’t like young Dalmatians at the best of times after one sprang at him from behind and started trying to bite his back many years ago. I noticed the D dog and managed to get him on lead well before he got close but there was a very snarly growl from Homer as we went past.
Homer has never attacked but can be inclined to growl a warning at other dogs and move off. I’m concerned that he may get himself into trouble if another dog reacts to him.