The Allen Collection has a shot of the Clan MacDougall from a similar angle to mine but the two don't match.
Anyway as far as I can make out there seems to be only about eight letters after Clan.
The Allen Collection only lists one Clan Campbell but built in 1937 and she doesn't match. I can't find an image of the one built in 1943 but 'Campbell' certainly seems to be a better fit to the letters as far as I can make out.
I'll double check at L'pool Record Library when I next visit.