Hi Guys,
Thanks all of you for the responses; combining them I have a clear idea about the steps to follow. This summer will visit a BGA club in the UK where I can get an authorized examiner, since there is no need for a written examination, just a flight test and the paperwork.
I haven't done any 50km or 100km with an instructor, but I can do this flight while I visit the BGA club.
Thanks again!.
P