Having updated the Columbia head unit a few weeks ago, it has started to ask for a PIN, I presumed this is for my phones to connect?

 

having put in my passcode for the phone, the screen just hangs with a ‘please wait’ at the top and the only way I can then use the unit is to turn it off and back on again. 
 

Any ideas?

You need to unpair and pair your phone to the car again after the ios13 update.

 

Thanks @Kenny R for the steer in the right direction.