Moogie, you sound a little sad to be off the 146. Fear not, there would be no shortage of local 146 drivers willing to jump at your 320 job should you wish to pollywaffle some more!
WHBM: Cityjet may use the -200 to LCY, but if its warm enough, the problems still occur. Above about 20C, a full pax load of 93 starts looking dodgy.
You are correct in saying that LCY is obstacle limited (off 28 anyway, I can't remember off 10 what the limiting factors are). It only becomes field length limited in the event of a tailwind.