Based on the email the link looks genuine. While I appreciate your support for the D-Link community, since the email originated from UK/Ireland and the firmware is not available in the United States, I have to insist that you not share the URL on this forum.
Depending on the country of origin, subtle manufacturing differences between different DNS-325s may cause issues if non-supported firmware is applied.
I will consult with a D-Link representative to validate the position of D-Link USA on this matter and will reinsert your link based on the outcome.