Anyone?

I've now repositioned the antennas so they both exit the RX pointing away from the rest of the ESC/Motor gear, and have picked the 'best' one of the two (from what I could tell) and routed it through the antenna tube. I've also removed the old extendable antenna from the 3PK, which appeared to make no difference anyway.

Maximum range before it drops out is still like 30m (my earlier claim of 50m was an overstatement).