Knowing Music teachers spend all their extra-curricular time from October half term onwards tearing their hair out to take Carol Concerts to Old Folks' homes etc, I think they would be very glad that this is no longer a compulsory part of the school year. Instead of this being a compulsory part of schooling, I bet Music Departments up and down the country will be pleased that this would be optional in secular schools.
It does raise the question of whether any references to traditions that are still deeply rooted in a particular religion's tradition are banned or become optional...
And the whole thing about my anti-monarchy stance is just a quick illustration that all laws that pass through this country have to pass through the House of Lords, a large part of which are made up of C of E Bishops who have been appointed by the Head of State (and Head of Church), the Queen.
So go ahead, have a healthy debate on this subject. But don't think it is an easy job. Propose that all state schools become secular, try getting that passed through as law, but my flippant comments are in response to the simplicity of this argument...