As far as I know Markb still has the NG servers on his domain, so you should be able to connect via /server netgamers.markbarton.me.uk.
Dunno if Markb has any problems with this though, if he does then my mistake
EDIT -
(12:08:51) (+Souls) so it's fine?
(12:08:53) (@Markb) yes
(12:09:01) (@Markb) its there just incase the NetGamers dns fails
(12:09:05) (@Markb) which it did this morning