at present the most authentic Triumph motor bike parts supplier is operating from website.
you have to provide details of engine & frame number to get item catalog and approx UK STG price ex-works.
KESC had over 500 of Cubs for their electric inspectors & surveyors. A stock lot of un-serviceable such bikes were dispose off sometime in 1984 & CD 175 was inducted.
You may be able to find cosmetic items from Karachi Motor Bike Scrapyard in Ranchore Line.
the main issue will be engine & transmission parts for which you need to be very careful. Carry the sample in hand to buy from scrap.