Bluetooth pairing problem with car

[Rolandtking]

I have an Honor 9 Android phone running Android 8 v.STF-L09 8.0.0.366C(C432). I like to listen to talking books in my car and have the phone Bluetooth paired to it. I download the books on my Windows PC, transfer them to the Music folder on the Honor and play them via my preferred app., Smart Audio Book Player. Until the most recent Android update, everything worked seamlessly – as soon as I switched the car audio to ‘Media’ the book would resume at where it had left off – but since this update it sometimes takes up to 15 minutes before the book resumes, or it plays other audio files via the phones built-in music player app. I have tried other book reading apps but these encounter the same problem. I thought I’d try and make Smart Audio Book Player the default music playing app (Settings – Apps & Notifications – Default Apps – Music) but this does not offer SABP as an option. Is there a way to remedy this problem, perhaps by reverting to the previous Android version or some other way? Finally, the phone function itself (making and receiving calls) still works OK in the car.