Las Palmas - many thanks for the comments, I traded in a Toyota Auris T-Spirit for the CT200 and the audio in the Auris was distinctly inferior, though it was battling against far worse road noise.
I read somewhere (online manual, I think, - can't find it again) that the audio system has inbuilt memory capable of storing a lot of music, but the manuals in the car do not mention how to load any, or even if the memory is actually there. Hence my query about manuals.
Currently I use a mini USB memory stick with many of my favourite albums on it, though it means the cover of the USB slots and the outer lid have to remain open.
I have updated the navigation maps from the original 2013 SD card to 2022 (I think) from satnavmapupdate.co.uk for £34.99, but I still tend to use Waze for the live traffic updates for some journeys.