This actually proves the point that the journalists who wrote about UK tech immigration issues (https://news.ycombinator.com/item?id=28377438) are missing a bigger picture: investors and major industries that feed IT sector with new opportunities and contracts (such as entertainment and construction) have already made their mind and have chosen Greater London over EU cities as their primary european hub [1] [2]. Bureaucracy around Brexit ramifications does exist, but it's not a decisive factor for the region to develop.

[1] https://www.youtube.com/watch?v=aqydTPDKQ44

[2] https://www.youtube.com/watch?v=SNXotuREZQ4