Firstly, Adrian; Welcome to the forum.
The format is correct (well its the same as my NIE anyway).
Trying to raise an online account with Endesa is very difficult. Many, including me have tried and given up.
It might be as well if you tried to obtain an NIE, since many things have changed.
Presumably you have tried to use the information on your printed bills?
I believe they need your name, the property address, the contract number, your NIE/NIF and the number of your last printed bill. Always seems strange that this information along with your bank details is enough for them to extract the payments from your bank but there always seems to be a problem when trying to register for an online account.
I don’t have an answer for you unfortunately, like most national institutions over here they are a law unto themselves. Maybe on your next visit you could call in to their office in Arrecife and see if they can help.
maybe some useful info here;
http://www.lanzaroteinformation.com/content/unelco-endesa-electric-bills-lanzarote
or
http://www.grupoestupendo.es/content/endesa-electric-company
Hope this helps…
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