I haven't attended many conferences. The two I have attended I've been an invited speaker. One for my MA Thesis I was invited to present at a national teaching conference and the other a methods conference at my University during 2nd year PhD (mist other students had to submit papers for selection). I have been invited again to present my PhD work this time at a prestigious data conference (mix of government, business and academics). Does it look bad that I've been invited to confetences rather than have papers accepted?

No I think it looks very good! It's better than applying to conferences and being accepted for a talk, in Biology anyway.

Conferences are always a plus, and sometimes will have some kind of publication of papers presented for the event. Even if not, publishing is significantly harder than attending conferences, so one would reasonably expect a candidate to have a few conferences under their belt with a much few papers (if at all) to their names. Now go network for that postdoc!

Good news then. There wasn't a publication from the first two conferences so I will ask about this 3rd one. This is my final year so I will also try and get a publication. Networking is key isn't it! All 3 conferences have come about from networking.