Hi, another Spanish couple thinking about relocating to Qatar.

The additional limited info. I have over what you got:
- Spanish tax authorities do not consider Qatar to be a "Tax Heaven" (unlike Bahrain or Oman)
- Also, currently there is NOT "Tax Treaty for avoiding double taxation" between Qatar and Spain (unlike UAE)
- Now, I have not heard that Spain (pls. correct me if wrong) has a requirement to identify whether money inflows to Spain have been previously taxed (unlike UK, for instance, where I believe you have to mindful when you bring in cashflows generated outside UK)

... following this (I insist it is not thorough, just based on a couple of facts), it seems that the tax-exempted money generated in Qatar could be transfered back to Spain without further tax consequences...
after these months since your question, have you got other evidence on the contrary?

Thanks a lot in advance for your answer