Can anyone recommend moderate priced hotel for a family of 2 adult and 3 children?
Free disposal of this suggestion, but maybe consider the former prison cells (now private rooms) of Hostel Celica if you're adventurous..
Back in 2008, I stayed at Hotel Emonec. It is in a great location and about as central as you can get ---very close to the main square. When I stayed there it was clean and basic, definitely a no frills hotel. I'd check for recent reviews since it has been a while since my stay.
You could have a look at Hotel Pri Mraku in Ljubljana. It's in a great location and an easy walk to the sights, some nice restaurants in the vicinity and the staff are great.
Or maybe an AirBnB apartment? I'm staying in one now that's a 5-minute walk from the city center and is far less than any of the hotels I looked at!