Hi,
have not designed this replica, took gerber files on our german forum, it is marked as "replica" and "untested".
Don't know exactly what You mean with "spanish design", indeed Investronica took part in designing Spectrums, but as much i know - the time +3 was released Investronica was already closed, Amstrad was not interested in another company based in Spain as they already had one.
Boards was shipped and should arrive soon. Will build and test them, and if all works great - will offer them here for a reasonable price with and without case as always.
kind regards,
-Viktor