Just to be clear (and for anyone reading this in future), that email is asking for your EU Operator ID and EU Flyer ID. A UK Operator ID and Flyer ID are no good.
I recently registered in France on their Alpha Tango system to get a Flyer ID. It was a doddle and my ID is valid in all EU countries.
Here’s the thread where I did it step by step: Operator vs Flyer in Europe - #17 by SimonDale
It is also easy to get an EU Operator ID on the same system.