Hmmm, seems like you caught them on the wrong day. Last time I went (albeit a while ago)I told my friend to bring everything including the kitchen sink and the tax guy looked at nothing! Except the FD9
Given you had already paid Spanish tax (surely proving you are serious) then I am amazed they made it so difficult (I expect he/she wanted to be on the beach!) and I agree I encouraged you to go in person (certainly as against using the post) but I suppose the Spanish culture is more towards dealing with gestorias than direct with the client!
If it is of any consolation - I do get the situation in reverse from my Spanish wife who (before we met) lived in London and had to deal with UK bureaucracy…..
Anyway I hope it is all worth it because I know many people pay less tax than they would in the UK (especially if they have a mortgage)
Thanks for sharing!