muck-savage,
I'm 99.9% sure that you can take the IR in Spain. I am going to do mine their. Here's the evidence.
From the CAA:
"Training for the Instrument Rating IR(A) must be in accordance with JAR-FCL 1. Training may be undertaken in a non-JAA state provided that the training organisation is fully approved in accordance with JAR-FCL 1 by the CAA, or, any other JAA State recommended for mutual recognition by the JAA."
From a Spanish FTO:
"Entry Requirements for IR/ME:
-Hold a current PPL or CPL
-Hold a JAA Class I Medical Certificate for CPL pilots
-Have previously passed ATPL (Frozen) Theoretical Knowledge Examinations (in any JAR state)
-Hold a JAA Class II Medical Certificate for PPL pilots with Class I audiogram testing
-Have a least 50 flight hours experience cross country"