There will be full en-route ATC during this event, in addition to Amsterdam and Heathrow aerodrome control. So even if Thames Radar doesn't show up for this event, Heathrow Director or London Control should sort you some vectors out :) Note: Obviously if a few people turn up you can't all share the same flight number. We recommend you substitute the last part of the flight number for a letter (i.e. if ICX110 is already online, login as ICX11A)
(http://rts.vatsim-uk.co.uk/upload/events/460.jpg)