LR 6.12 Margins on print different to display

I'm trying to print on some Hahnemühle Photo Cards which are 100 x 150mm / 4x6" within LR 6.12 on an iMac using macOS Sierra 10.12.6

Page Setup: 100 x 150mm

Non-Printable Area : 0mm on all sides

The layout in Lightroom looks like the screen shot below. 3mm margin on all sides and everything looks how I would like it :

However when I print, I get the following output with the bottom margin cropped off:

I've tried numerous settings but each time I cannot get the printed photo centred with equal margins.

Does anyone have any ideas?

Thanks in advance!