The outer porch door was unlocked. Our house has a long hall with the sitting room at the back so if sitting room door open I can see front door from sofa if that makes sense. About 10 minutes ago I thought I heard someone in the porch and then the dog barked and when I looked up I could see our letter box was opened up and there was someone looking through. Dog was racing down the hall and jumped up at door barking and whoever it was disappeared leaving outer door wide open.
At home alone with kids and completely freaked out - I doubt they had any good intent. Glad dog reacted though she's a soppy spaniel so not exactly top grade guard dog but she certainly earned her bed and board just now. Hopefully she's put him off the idea.