I live near HP9 1SJ. My aerial is routed through a powered 8 way splitter amplifier and to the FVP, then to the TV.
My signal is shown as 100% by the FVP, but this has not been an issue for any of the other 4 freeview receivers in the house.
I've ordered an 'unpowered' splitter and also an in-line attenuator. And will update when I have results.
As for Humax support, after it took them 4 days to respond to my first email question, they now seem to respond within 48 hours.