Hi Satdog,
Agree with Dave pictures would be great and any original documents even better.
I should qualify "I'm no Claud Butler expert". The letters CB in CBguy actually come from the place in Nova Scotia that I hail from. Dumb move.
Dave is correct, between '76 and '85 the Holdsworthy company lumped all their Holdsworth and Claud Butler models together in a sequential six digit number system always beginning with o(s). Before take over of Claud Butler in '57 and until 76 Clauds had been numbered separately. Many of the Holdsworth Clauds were simply clones of Holdsworth Models at least in early years.
Looking at catalogues on Kilgariff's site, like yourself, I don't see a Claud model that is equivalent to or the caliber of the Holdsworth Pro - in '78 the top model built with 531SL with 74deg angles and chrome ends. Is there a model name on your frame?
In chasing the numbers it has come to light that Holdsworth built "specials" for other shops that were numbered differently in the earlier years but with the new system all frames were in the same system. The shop in Dublin possibly ordered your frame as a "special" build, requesting a top end road frame, but specifying the Claud Butler brand rather than Holdsworth. Interesting if you know any of these details.
Post takeover Clauds sometimes get a bad rap as not "real clauds" but you obviously have an excellent quality and unique frame.
Perhaps somebody with more experience re this model Claud will have more to add. Pictures would be good.
Doug Allen