WHBM
You obviously enjoy the efficiency of LCY, and not looking forward to Thiefrow chaos, so try LTN. EZY flights at similar (slightly later) times to Belfast International, at time of looking, cost £135 return.
Train from the City (Moorgate, Blackfriars, City Thameslink, Farringdon, St Pancras) to Luton Airport Parkway in about the same time as the DLR takes to LCY.
No hot towels!