I am one of those FISOs on London Info and a PPL as well, so perhaps I am qualified to answer one or two questions.
If an aircraft is near to an ATSU who is able and WILLING to give the aircraft a service particularly a RAS or RIS we would transfer it to them. Not all ATSUs are willing to give a service due to workload and/or staffing.
If we are able, we can split off the busiest freq normally 124.6 the south east freq, and have a dedicated FISO for that freq, often staffing at Swanwick precludes this though.
Last night an aircraft called me over Northern France going to Newcastle and the first radar equiped unit I could tranfer it to was Coningsby in Lincolnshire who unusually were open, normally we would transfer it to Waddington which is H24.
I would certainly agree that what is required is H24 LARS coverage nationwide, but who pays?
If Romeo Romeo would care to E-Mail me I would be delighted to show him around the "mysteries" of the FIR and London Info.