Thank you for the question. There are quite some things going on in this period, though much more will take place in London in December. Here you will find suggestions for some activities or concerts in this period, but unfortunately most of them does not have much to do with Christmas.
On all three dates you can see the show named Raymond Gubbay Limited presents Classical Spectacular in Royal Albert Hall in London. On 24th and 25th of November this show will be available twice a day. There are quite some concerts and classical events going on in the same period, so on November 24th there will be a Robbie Williams concert in London, you can see the Swan Lake in the Royal Opera House and on November 25th you can enjoy a Rolling Stones concert in the O2 Arena of London. But, as you can understand this does not have much to do with Christmas, so it might be hard to find a real Christmas event.
Some websites tell of Christmas carol concerts in St. Pauls Cathedral every evening from November 25th, but this is not confirmed by the website of the church itself, and not many websites write about this, so guess this is only a rumor and some wrong information available on the net.