Opening Price

Hi
I'm currently putting something together which entails having a specific, daily, 'opening price' point.
Whereas I realise that, unlike in stocks etc, fx does not stop and start as such, I nevertheless need a good time upon which to rely as the start of the European action each day.
Now, here's the confusion at my end.
Does Europe kick off with the Frankfurt or London open?
And, is there some significant action in the hour before whichever it is?

Any advice gratefully received.
Thanks.

'' Normally '' order books get '' passed down '' from Asian to the European Desks, and depending on the volume/liquidity Frankfurt (am Main) gets the first go, thereafter London steps in to the game as well an hour later at 08:00 am which is already 09:00 Frankfurt time.

Best hours to trade (mainly for cable) are the Frankfurt and London open. (which are both starting at about 07:45 local time)

Best.

That's helpful, thank you.