Tbh I don't know enough about EU to decide whether it was a good decision or not. My impression is that it is petty dumb given they lose the security of the EU and complicates things for UK citizens who work in EU and vice versa.
Good god was that last left of the trip a mess. So we got to what we thought was our penultimate stop. Well we had 10 seconds to get off the train (and we didn't), and then our friend missed his train back to Cambridge, because he had 30 seconds to get across 3 platforms over a bridge. So we hopped on the train that said Cambridge from King's Cross, and it happened to be the one that stops at every. fucking. stop. So a 20 minute trip took over an hour.