Barking at night

[Frizz1986]

I have a 6 year old westie and for the past few months she has been barking during the night and we of course made the fatal mistake of going downstairs to sort her out as we assumed she needed a wee but she didn't and now she's barking almost every night a few times a night.
I think sometimes it's because she can hear the woman next door arriving home as she works shifts but other times there seems to be no reasons at all. We have an 18 month old who thankfully doesn't tend to wake up anymore but we can't just let the dog bark it out as we don't want to risk the toddler being woken up or wake up the neighbours (live in a semi)
Any advice as to what things we could try to stop it. She is a barky dog anyway (barks at loud noise or when people go past the window or visitors as she wants to see them) I think it's a bit of small dog syndrome because as soon as she sees people or dogs etc face to face she is all lovable or shy.