Agreed Windy, this isn't like the Headcorn operation at all, far too many potential conflictions.
HD has the answer though, just say NO. Easily justified during any daylight hours due traffic in the LTMA.
With regard to Farnborough traffic routing south or south-east. There could be anybody at GWC up to FL64 right now, without any need for permission, so it ain't an ideal situation as it stands. Do operators realise that to get into / out of "the EGLF Clutch" you've got to transit Injun country? (Class G). I doubt it.
Rgds BEX