I am not 100% sure but I think 1149 and 1150 were converted to super standard sometime in the 1970's to run on the enterprise as CIE wouldn't risk a mk2 set north of the border.
Also I seem to remember 1508 and 1509 were converted sometime between1988 to 1989. This was due to the withdrawal of all timber frame stock following the introduction of the mk. 3s