Without a JAR license you require 1500 hrs in a multi-pilot aircraft (ie 2 crew above 5700KG if not bigger). obviously with 250 in the -400 you only need 1250 more multi crew. Not sure if you have it or not. A number of guys were turned back last year by the ICAA for this reason.
If you do have it, give old Jerry a ring in LGW. He'll sort you out..sort of