RNS: NED buying5 Feb 2018 12:03
"Scientific Digital Imaging plc, the AIM quoted group focused on the design and manufacture of scientific and technology products for use by the life science, healthcare, astronomy, consumer manufacturing and art conservation markets, announces that the Company was notified on 2 February 2018 that, on that same day, David Tilston, Non-Executive Director of the Company, purchased 45,000 ordinary shares of 1p each in the Company ("Ordinary Shares") at approximately 31.46 pence per share (the "Purchase").
Following the Purchase, David's beneficial interest has increased to 70,000 Ordinary Shares representing approximately 0.08% of the Company's issued share capital."
So he's more than doubled his holding. In fact, almost tripled. :))