Place to hire for party (Lisbon)

Dear All,

I've seen a few posts about restaurants and good places to eat in Lisbon. I am helping to organise a 50th birthday party for a friend in Lisbon in October. Can anyone recommend a good tapas bar or small restaurant that could accomodate up to 20 people in Chiadao / Bairroa Alto or close areas round there. Nothing flash or too fancy, that will happily take kids as well as adults (well, that's probably most places here...)

Let me know what you think and thanks in advance for suggestions

Anne