On Wed, 8 Nov 2017 08:54:54 -0800 (PST), whisky-dave
wrote:

snip

fort eh last 2 hours it;s been full on at 705 watts.
If I switch of teh I rocker it;s LED goes out the other II LED remains on and the power drops to 0W, a few mins later I hear a click the same LEDs on and off but the power goes to 1045W.
Switching the I back on power 1734W
Switch II off 702W

In addition to what has been mentioned elsewhere, the link suggests
you have a 3 level (switchable) heater, where one element is ~700W and
the other 2000-700 = ~1300W.

So, you have choice of output powers of (nominally) 700, 1300 and
2000W.

The thermostat *should* function on all / any settings (so you should
measure 700, 1200 or 2000W or nothing).

The 'overtemp' switch should also work on all / any and that may or
may not cut in (open) before the thermostat does, depending on what
wattage you are using (input energy output load).

The 'on' indicator may or may not indicate it is heating or that it is
just on (depending where it is in the circuit).

Anything else would suggest that it's either wired incorrectly, or is
supposed to work like that (instructions)?

Cheers, T i m