I've put a link in the Cityjet thread to another report issued by LCY.
That lists all versions of the RJ separately, and seems to state that only the RJ100 version has breached the noise limit.
Interestingly, the Dornier 328JET apparently is also causing problems - which might explain the predominant use of the turboprop version by Sun Air in the past. With what variant is the new LCY-BRE route served?