@Lacasta: welcome here! I am not an authority on the subtle matter of licensing, but I feel inclined to think that the ultralight license (why the Brits want to talk of a "microlight" is an eternal mistery to me
) being a national document, only the authority who issued it can honour the hours you fly on it. That is to say, the UK CAA (or my own Belgian counterpart, or whoever) can never take into account the hours that you fly on a Spanish ultralight licence.