Orange clip in the boot
 

Made the mistake of undoing the orange circuit breaker thingy in the boot the other day. As a result the car wouldn't start. I noticed that the clip wasn't locked properly so after an adjustment in the clip, the car started.
However, for the rest of the day, I had the "check Hybrid system" warning on the dash. Later on, after having a mild panic and searching the site for a way to reset the warning, it just went away. Go figure.
Now, it is doing a few odd things such as not going into gear when you move the leaver sometimes so I occasionally need to move the leaver twice. Also, it seems to want to turn on the motor more often when cold (last week I could get to the gate before the petrol motor started), now it starts within a few seconds and overrides the EV.
Can disconnecting that plug somehow reset any changes made by the dealers or something?

All seems to have corrected itself. Lesson learnt: don't fiddle!

The plug would have nothing to do with you having to do the lever "twice" or any of that. that's just in your head or something that's always happened but now you're thinking too hard about it.

putting the car into drive does take a definitive effort of making sure the lever bottoms out when you move it to the D position. if you go too fast, it won't go. Which I like anyway as a safety measure. It's good it requires deliberate action so mistakes aren't made.