yes i think Wagamama started in the UK in the 90's - or at least that is where i first came upon them. I agree about the seating, but in the Carindale store (and I can't speak for others in particularly) the seating is at least a little more separate bench-style seating. My memory of some of the UK places (London and Glasgow) were just rows and rows of benches, which is not the case in the newer stores here.
Hopefully the children eat free deals will take off here and Wagamama will get the idea to spread it to their other stores! Why not ask?