Surely the EU would maintain its stance on such unilateral declarations of independence and as in Spain, it would support the UK in sending in riot police to brutally put down the rebellion. If not, why not?
Gosh, the lengths some people will go to try and paint the EU in a bad light...
The Catalan situation was very different to Scotland: In Catalonia, the regional Government held an illegal referendum that produced a very low turnout, and then unilaterally declared independence - again, against Spanish law, and despite overwhelming evidence that at least about half the Catalonian population wished to remain part of Spain. You could well argue that the Spanish Government wasn't being entirely reasonable, and that in some cases the police they sent in also went too far in use of force. But nevertheless, if the Spanish Government was to uphold Spanish law, sending in the police was arguably the correct thing to do. For someone who keeps trying to make out that the EU unnecessarily interferes in member country's affairs, I find it surprising that you'd complain when the EU, quite correctly, treats Catalonia as an internal matter for the Spanish Government! One might almost think you're deliberately trying to paint the EU in a bad light, no matter what it does.
It seems pretty implausible that anything similar would happen in Scotland, since the UK Government did allow the Scottish Independence referendum, and made it clear a vote for Independence would have resulted in Scottish Independence.