It is both crowded AND bearable. If you go there with the knowledge that it is going to be crowded and you may have to plan a little more wisely to get things done, you will be fine. You will have a whole week, which is plenty of time to get everything down - crowds or no crowds - and honestly, even though the holidays at DLR are busy anyway, it doesn't really get unbearable or truly uncomfortable until after Christmas ends. So I would say that if you are at DLR from the 19th until the 26th, you will be fine. You will be leaving right before the crowds get hideous. Now if you were planning to be there on New Year's Eve, I would say run for the hills and don't set foot in DLR, but the 19th - 26th is nothing to be scared of. Lots of folks who are on their breaks stay home or with families for Christmas and then once that holiday passes, they all pack into DLR for the remaining vacation week. We were at DLR the last two years right before Christmas and it was very busy, but we managed it fine. It will be fine! You will have a great time - it is beautiful then and very magical!