I have an ECU and an alarm that I had problems with, and replaced both. Not sure what the issue was or if they can be reset. I wouldn't mind having a spare set around

 

you can pm me.
I can see what the issue is and fix them, then send back out.

 

By no means am I an expert... but the app absolutely works to reset the adaptive values related to throttle. Normally you could only do this with a high end tool to get into the ECU.
The app is very simple, what you see on the screen shots is all there is to it. You connect to the OBD device, hit reset on the app... hold your breath, that’s it !
I tried the iCarsoft, nice scanner for the money, reads lots of speciality codes for Rover, but can only reset fault codes, not idle or throttle pos., Same thing with Hawkeye, didn’t try it but got that from there support.
For $60 Bluetooth ODB dongle, and the free app that comes with it, and the GEMS app , you’re good to go!