Well after the rather useless info here, I managed to read the Spanish foros on how to get LDN.
There are NO compounding farmacias in mainland Spain.
You have to get your hands on a packet of 50mg Naltrexone and do it at home, but this is what I've been doing for 2 years, so no problem.
To obtain the Naltrexone, you can talk a farmacist into selling it to you, or get a private prescription. I'm off the farmacia soon to go and talk to their boss.
It costs - 43 euros a packet. That's 43 euros for over 10 months of LDN.
That's a lot cheaper than in the US or Canada.
Once I get the Naltrexone, I'll put up info on the LDN Trust and try to be of help to others who may find themselves in this position and who don't have much monthly income.