Pace - was this an IFR flight filed via Eurocontrol, with London Control your first contact unit?
If so, you should not have been dumped out of CAS (and thus lost the LC service) unless you asked them to do this.
If however your destination is not in CAS (e.g. Biggin which is Class G) they obviously have to drop you out of CAS somewhere... the question is whether this was too early for you. OCAS airports don't have a STAR so a passage of Class G cannot be avoided.
Some pilots have been dropped out much too early, leaving them to fly OCAS under the LTMA at 2400ft, in IMC, with no radar service. The recommended action in this case is to file a report. LC is not supposed to do that.