I actually agree with you for once - the Lib Dems looked stupid in their yellow T shirts and the Brexiteers looked sinister turning their backs like the Nazis did in the 1930s.Today’s shenanigans in Strasbourg were disappointingly childish. Turning backs and wearing T shirts is not likely to gain any chance of renegotiation ,pretty pathetic but in many ways sums up our political class.
One thing however I wish our media would stop calling it their national anthem.They are not a country!
It certainly shouldn't be a "national anthem", and I am not quite sure why the EU needs an anthem.
Any anthem though is not "theirs" it is "ours" as of course we are still very much part of the EU.
Regarding renegotiation - I thought that it had been made clear by now that there will NOT be any further renegotiation.
Brexit will either be a no deal (followed by years of us trying to make deals ) OR no Brexit at all.