Christmas in London from overseas

Hello all, I'm an overseas member, from northern Italy.

Last July with my family we towed up to England,and stayed for about a week at Abbey Wood, near London. We had a marvellous time. Now my daughter (17) and my son (14) are insisting that we should take another trip to London, this time for Xmas and/or the New Year. Considering it's about 1500 kms from my place to Calais and that Abbey Wood is fully booked in those days I'm not very convinced about the idea. Has anybody else ever toured through France in Dec/Jan? If I decided to do the trip what other convenient site would you recommend around London? Many thanks for your answers, ciao, Marco