Right I have good news. I'm not sure if it was the ignition that did it or the new sd card that I got.
I used a sample file that malbry kindly provided to me (UK football stadiums) .
I swear to god I could not get this to work a few weeks back.
So the steps that I did this time:
The car was turned on. Slotted the sd card in and went to Personal POI in the menu in Nav Mode.
I could immediately see UK Football stadiums there. There was literally no 'importing data, this may take several minutes'. if there was one, it was so quick that I literally missed it. I could see the option to turn on audible alerts for the football stadiums.
I'm not entirely sure if it was the ignition that did it. I switched off the car, after I got it to work, and took the sd card out, put it back in and I could still see the POIs just fine with the ignition off.
The only other possible explanation is that I got a new sd card from amazon.
The card I got the second time was slightly different - I don't know if this played any part?
The first sd card was NTFS which I had to format back to FAT32.
The sd card I used today was already FAT32 so I didn't have to do anything to it.
Bear in mind that I have a Mac, so formatting to FAT32 is slightly trickier as it's not native to MAC OS X. Although I doubt this played any part.
mp3 playback was fine with the original sd card (after having formatted to FAT32) so I'm not sure if the first sd card is at fault here.
For reference these are the two sd cards I bought:
pois didnt work:
https://www.amazon.co.uk/gp/product/B014IX02KC/?tag=amazon0e9db-21
pois worked:
https://www.amazon.co.uk/gp/product/B00422F8XQ/?tag=amazon0e9db-21
hope this thread helps anyone who has been unsuccessful in getting cameras to work for them.
P.S I haven't actually got cameras to work yet, I just deem that POIs work based on the sample file.
I will try Camera POIs this evening when I have more time in my hands.