kharmael
If I'm IMC under a traffic service and the controller gives me traffic info then I'd manoeuvre accordingly using the picture in my head or TCAS
You either fly in very quiet class G, or I'd be worried about that statement. If you are really in full IMC (not intermittent) and you rely on your mental picture and TCAS to show you the way to avoid called traffic, then you are increasing your risk. I accept against one or two contacts you could do it, but anywhere busy and you are, frankly, delusional about your mental ability, and ignorant of how TCAS actually displays... not having a go at you, just worried that you might think that TCAS is a good subsitute, or that you feel you can retain a complete mental picture of called traffic to allow you to weave your way through it.
Genghis,
I appreciate you might have liked an earlier heads up, and notwithstanding what
Amexgull says about having a conversation with the pilot (you can do that at some units, others are just too busy), but if you follow
ShyTorques advice and add an extra dimension to your flight planning, then an instruction to freecall etc won't come as a surprise.
I assume you plan meticulously for your VFR flight... it is not difficult, nor time consuming, whilst doing that planning to take note on a chart of the units you will be flying near, and then having a comms plan for the flight (i.e. anticipate where you will go from one unit to another for a service). If you then need to fly IMC, then you have the information to hand.
Otherwise, as ShyTorque also states, another option is acceptance that you cannot continue VMC and turn around.
In an ideal world, we would have a joined up LARS service... you maybe would not get handovers from unit to unit, but the next unit would have your details passed by an assistant and you could then be told to "continue with xxx" ('continue with' infers that you are not getting a radar handover, but that the next unit has your details, therefore instead of a freecall with all of your details, you just need to give callsign).
Unfortunately, HMG does not wish to pay for this gold plated level of service, and unless it makes sense for individual units (safety of their IFR traffic for example), then they won't provide it either as it costs money, money that the GA does not pay.
Amexgull is correct, controllers are there to provide a service, amongst other things, but full planning/forethought by 'the customers' makes the job easier for both.