Re : As you know, if you are a none Spanish resident, the buyer will retain 3% of the sale value and pass this on to the tax man, however, I don’t know what happens after that.

I’m posting this as I’m full of sympathy for your predicament and this may assist you after the sale at least. I was lucky I guess as bought off plan and thru bank guaranteed seller else it could have happened to us as we take people at their trust.

Costa Del Sol : I paid 138k Euros plus the 10% costs  in 2005, sold July 2014 for 169k they witheld the 3% tax on selling. After ALL costs from beginning of ownership to end there was no profit after ALL costs were taken into account which include all your fees on selling ie realtor, lawyer etc.

If you take the advice given by the employed experts (Mark Stucklin) on this web site previously (see link below) you will lose it you wait over three months since sale, They said it had a 3 month deadline after sale to submit Form 212 & claim it back.

After reading that I thought dammit as I sold just over 3 years previously so I didn’t pursue or put in a claim, in my case after sale I thought it would run its course and the refund would follow auto some months after the sale.

Then last Sept 2017 I thought I would ask the question, I called my lawyer over there and set up a meeting while on holiday.

To my surprise he said he can still make the claim and lo and behold I received a four figure refund directly to my bank last week (3 months after he posted the claim, he had said could take 6 months)

Good luck Bonehead52 but don’t give up and don’t believe all that the so called experts say & get a couple of expert opinions, hire a good lawyer, an independent local one that comes recommended by someone who lives in your area of Spain as I did back in 2005 and never had a problem other than a bit slow at times, he’s in Fuengirola but retiring soon.