I haven't seen anyone do it (some people seem to cycle and leave their bikes in the rack outside the station but not sure of the wisdom of this). Bikes aren't permitted on the DLR and I believe the stated policy is that folding bikes are only allowed if completely enclosed in a container but no idea if they actually enforce this. Have you considered cycling the whole way to work? I sometimes do from HOP to my office in CW and it isn't a bad journey. Takes me 40 minutes and think it works out at about 10k each way.