Radio doesn't remember last station on restart

[Octatonic]

When I bought my DS5 18 months ago the radio would remember the previous station from when the car was turned off to when the car was next used. For the last few months it hasn't, it just defaults to medium wave static. It remembers all the presents etc but I have to press Dab then the preset I need every time. Not sure why it changed or how to rectify this, tried everything and nothing in my manual about it. Any ideas?

[Stickyfinger]

Does that radio have an internal battery ?

[Octatonic]

I don't think so. It's built in and no tech specs mention a battery.

[myglaren]

Have you checked the fuses, one should provide a permanent supply to keep the settings in memory.
Some cars have a shunt fuse, normally in the 'customer' position but pre-sale in the 'dealer' position to reduce or eliminate battery drain for cars stood for months on end. Check that this fuse is in the correct position.