The winter pack pump does indeed live on the inner wing, driver's side. Don't confuse it with the one by the radiator that is used (only) to circulate coolant when the engine is shut down hot. Both are fitted on cars with the winter pack. They look like the same part IIRC.
There is a setting on the climate panel to enable the pump. If not set, it runs all the time, IIRC.
FWIW, I removed my pump when I did the LPG conversion (and added a vapouriser and a load of plumbing into the loop) and it has made no difference to the heating whatsoever.
My understanding is that this pump's chief purpose is to allow coolant circulation to continue when the engine has been stopped, heating the cabin from residual heat in the engine.
It MAY be used to supplement coolant flow when heating demand is high but, as I say, I haven't noticed any difference in that regard having binned it.
The heater matrix circuit receives coolant flow regardless of the thermostat position. In fact, it forms the bypass circuit before the thermostat opens so has the full might of the engine coolant pump behind it.
I would imagine a tiny electric pump (and the flow they provide is only a dribble - I did investigate re-using mine for irrigation purposes) would be neither here nor there once the engine is running. They are probably more of a restriction, especially when you consider the length of pipe involved.
The pump is plumbed between the HBV and the inlet to the heater matrix, BTW.
If the wiring is there there'll be a 2 pin mini timer connector dangling (or taped up) somewhere under the coolant expansion tank.
Kevin