Rangemaster 4 door fridge freezer — bleeping alot == DXD910

I’ve checked previous posts but nothing helps…… This machine works fine coolness wise but it is bleeping every 20/30 secs as if the door is open (but its not) there’s no error code, the door switches work ok and both the doors close ok
I’m not that familer with these 4 door machines so any help would be great….. Ta

Ser No: 90170002416