Just because the stock is on the Spanish market doesn’t definitively mean yes it can or no it can’t.
If, say, it was held in Euroclear then it could be cross bordered easily to HL
We’re it, say, in custody in Clearstream in should be able to be cross bordered
We’re it, say, a listing with a dual listing in London it should/could/might be entirely fungible and the registrars would works some magic on your behalf
I guess the question
What scheme! Where? What stock? Held in custody in what system?
I’ve transferred many a stock via the dreaded XDL messages in crest to get them from (foreign depository) to the UK. It’s not rocket science and generally HL should know what they’re doing. So there must be a real quirk some where.
If you tell me the stock is Santander I’ll be surprised… so what it is?