I have a mint one, came from my 60S, now has a 60SX sensor fitted.
1.1 and 1.2 sensors are same, but if your dials don't have a temp gauge (just a too late light) then you need this one i have.
£5 if you want it, £30.02 for the SX one from a fiat dealer, S model sensor is about £25 AFAIK
scrappies will be able to get you one for £3-4 but no gurentee it works the job, and the one I got my SX from didn't know of the difference either (one is a bimetalic stip type, the other is a temp sensor).
arc, I think you repeated yourself there, you said both are for the gauge they are not!
The one on the back of the CYLINDER HEAD is for the gauge, and AFAIK its also for the ecu, I don't know of any other sensor on the engine.
For the RED BOTTOMED SENSOR WHICH MAKES SX CLOCKS WORK (rather than being either 0 or 1) FIAT QUOTED ME £30.?? NEW, from a scrappy a red bottomed one that worked £2, but to guerentee it would work would need to be a £3-4 but I wouldn't know how they test em.