Discovery 4 iPhone issues

Hi, just bought a 2010 Discovery 4. My iPhone XR paired with no issues and connects every time I get in the car. All works fine apart from two things.
1) If I press the green make or take a call button on the steering wheel or on the touchscreen, it redials the last number called. It shouldn't do that, it should need pressing twice for that to happen.
2) Not all of my (4854 ‍) contacts in my iPhone are displayed in the Phonebook. I can search for name that I know should be there and it doesn't show.
Can anyone help with either or both of these two issues?
TIA.

The D4 phone connectivity system was built before the phone software was written, and unfortunately the fruity phone company like to change software, which aren't always backwards compatible.

I've a Droid, which is universal and just works, no fuss, no messing, no compatibility issues.

Thanks @Nodge68 I guessed it was something like that. I'll have to rely on Siri which, to be fair, is probably safer and quicker.