There overall is a big misunderstanding regarding what controlled airspace is for.
Controlled airspace is simply there so that pilots can tell that there is an area within which;
a) They may have to obtain a clearance to enter;
b) The VMC minima may change
c) The service provided by the ATS unit may change.
d) The equipment requirements may change.
It is not a no-go area.
Having said that, no pilot would say that an arriving flight at an aerodrome should be delayed or have an extended routing during the initial. intermediate or final approach phase or even the missd approach phase due to an enroute transiting aircraft.
Taking that in mind, a pilot is quite entitled to fie a plan and at the appropriate time request a clearance through controlled airspace within which their licence and aircraft entitles them to fly. If ATC are unable to issue the clearance, they are required to issue a time check and an expect onward clearance time. Often this will be a rough estimate of the delay.
If the delay caused by waiting is longer than it takes to fly round that airspace then I think it makes sense to fly round.
I have not seen flow restrictions in the Solent CTA and associated CTRs and consequently, they are below their IFR capacity all of the time. Note I am not talking training flights here!
A number of issues in the UK make the situation more difficult for units such as Solent -
Poor navigation by GA VFR flights
Poor Radio procedures
Lack of co-ordinated flight planning system i.e. file a VFR flight plan to transit solent airspace and they probably will not get it or if they do, they may ignore it.
Funneling of traffic due to Class A airspace, Military airspace and busy GA / glider aerodromes that surround the CTA.
The silly idea that the "recomended crosschannel route" starts overhead their field and is not far off the runway centerline!
ATC are required to issue a reason for refusing a clearance. If taking the whole picture into account, a pilot feels that they may have been wrongly denied a clearance to fly VFR in class D airspace, there is a form available from the CAA, GASCO and AOPA which they can fill in to report the matter.
As to the matter that Solent Radar is not a LARS unit - True.
FIS is not a LARS service.
Check out the Eurocontrol website for the future proposals regarding controlled airspace. See what the UK people attending the various meetings (you can read the minutes) are doing. Or more of what they are not doing or understanding! However, it will give yo and idea of what the future holds regarding airspace.
Regards,
DFC