ppheli
We cannot normally refuse you entry to any LS in the LCTR.
However, if a LS does affect LHR ops, and departures or arrivals are stopped to get you in/out, then you can expect the same delay as the jets.
i.e. If aircraft are holding at BNN for 20 minutes, then so will you. This makes it fair.
Also, CAP493 (the Manual of Air Trafic Services) clearly states that SVFR flights are not to hinder IFR flights.