Whilst privatised, Airbus is still very much a political animal. Back in 2007 when EADS was formed and the UK government decided to leave the consortium, there were already rumours about moving wing production 'in house'. But Airbus instead took complete ownership of the factory and has kept production running in the UK, as it didn't make financial or technological sense moving it to e.g. Germany or France. One key reason to this was UK membership of the EU. Conversely, France and Germany retain around 11% each and Spain holds around 4%.
There are very strong franco/german thoughts about Brexit, and they are far from friendly and understanding. They feel betrayed, and that the political class in the UK are a bunch of idiots, to put it bluntly. Right or wrong, that's the state of play.
In this environment, and there being no fundamental reason why Airbus should retain such a key element of production in a 3rd country, the possibility of moving wing fabrication to the continent has gone from 'unlikely' to 'plausible'. It is highly unlikely they'll do it out of spite, or if it has obvious negative consequences, but I could see wing production having migrated to another EU country within the next 5 years. And if Spain is able to increase its ownership share, it could be the recipient.