The Landrover Discovery 4 is available as of GOFAR app version 1.2.0.
Diesel is currently undergoing testing and should be released in the next couple of weeks.
In the next few days we will release trip "tagging" which will allow you to add short tags to trips. Longer "notes" is something that has been requested and is in our feature backlog.
For your tonic function, you're absolutely right that the Ray should not go red in this situation. Our engineers are working on this problem and we hope to deliver improved feedback soon.