Channex used to base herlads at NCL to fulfil the Royal Mail contract at night.  I think this was the case in this photo.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/130275500@N02">G B_NZ</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/130275500@N02/29461694640/">Channel Express Herald G-AVPN at NCL?</a>