Hi Carolyn, one benefit of having a fiscal representative is that all correspondance goes to them, so no problems with not being there to receive and action your mail..........the tax office will not post to an address not in Spain.
In 12 years I can not recall having, I'm pleased to say, any correspodance from the Spanish tax office. Its bad enough dealing with the tax office in the UK where we speak the same language!!
Whether your property is worth 75,000 euros or 750,000 euros assuming you do not rent it out your solicitor has exactly the same amount of work to do in submitting tax returns on behalf of the owners of the property...........hence the flat scale of charges they have.
Regards all
John