Ariel Owners Motorcycle Club

Hi All, I have just bought an Ariel fitted with a Brooks Pan Saddle is it a repro or what, the leather looks new but the frame looks pitted under the paint and stamped on the frame is '10 To 12 Stone' it does not really go with a 29 Ariel and is resting the tank so I think I will have to extend the saddle tube coming out of the frame by a small amount or will a later saddle fit better on the existing tube any advice from 28-29 owners thanks. Clive.