D3000 video and Ethernet no longer functioning on W8.1 with Dell XPS 13

[Molds]

XPS13: -

7VYZVW1
8Z3SVW1

Dock: -

Dell D3000
ACP075EU
1304000319 and 1301001697

Both XPS machines had been working fine with the docks until recently when they stopped working for no apparent reason as per the description in my first post.

Thanks.