I used to travel from Honor Oak Park to London Bridge, then bus to Gray's Inn Road (earlier is better, as Dukesdenver said). After Xmas they changed the timetable for trains in the evening, so coming home was even more horribly overcrowded. However, with the snow at the beginning of February and all the faffing around trying to get into work, I discovered a great bus route, which doesn't really take any longer, and I am saving loads of money on train fares! Try the bus!