No import duty as Spain is part of the EU as is Germany.
Getting any warranty actioned if you need it is another consideration. So in effect you will be buying it without a warranty.
The first item is located in Germany, the second in Spain. You will have to change the plug to a 13amp plug. I see the German supplied Vac will have a Shucko to UK plug adapter included. 3000 watts is 13 amp at 230v. That probably needs a 16 amp plug fitted which is a whole new issue if you don't have a large generator.