Straighten Up,
When LCY is landing 09 traffic will be at 2,000ft crossing Tower Bridge. Aircraft are descended to 2,000ft on the downwind leg before being abeam LCY airport. Leaving plenty of space with LHR westerly arrivals.
As peter_griffen says it's more of a potential conflict point when both are on Westerlies as the stop altitude on departures off 27 @LCY is 3,000ft. With a good headwind the E-Jet can be above 2,500ft as it turns,or shortly after turning north abeam the dome. It's not too uncommon to get a TCAS traffic alert under certain conditions.
RJ.