Hi, thanks for your comments
yes, you were quite right the ET5420 doesn't have external sense but i did plan on modding it. I still haven't found any further detail.
Dingchen DCL6104(A) i hadn't come across this one before, the spec sheet looks similar to the kunkin kp184 but with a TFT display and no external sense, but interesting nonetheless.
But your suggestion of the Tenma brand from CPC the spec looks better, it has better measurement tolerance, LAN for comms, one years warranty and requires no mods.
Kunkin KP184, needs stripped and modified as suggested by several people.
Head says Tenma but the heart says Kunkin because i like doing mods