no, you're right, there IS evidently something forcing the iscv drive, or making the system think it needs a fast idle..
OR - as you say there is a fault.. I'm just trying to clarify the position with the TPS to avoid you chasing problems that aren't there unneccesarily.
Simon SECS is probably best placed to understand the conditions that would make the system think it needed a fast idle.
The other possibility is that the iscv drive output stage in the ECU is broken, forcing a permanent earth on pin 34 and driving the iscv on all the time - hard to know without looking at the signal with an oscilloscope to see if it's permanently low or switching (as it should be). Try briefly shorting pin34 to chassis with a length of wire whilst it's running and see if the idle raises even further - this would indicate if the valve is being driven hard on or only part on..