Just done a google

[Silkie]

for "secondhand charts" and the Bluemoment listing came out first.

http://www.bluemoment.com/writing.html" onclick="window.open(this.href);return false;

I'm trying to find out which area was covered by 2551, listed as n/a by UKHO.

[Rowana]

I have a catalogue from 2000, and 2551 does not appear on that, so it must be an old chart. If it ever existed in the first place that is.