I have put two lots down , note both for your engine Series but one for adjustable camshaft sprocket so read carefully.
pages 286 287 are for the none adjustable and 288-291 are for the adjustable sprocket.
I would try on eBay, quality varies but it may be a case of what ever you can get given the age.
The belt tensioner seems even rarer. I have never used one, just relied on the many years of experience in the trade and rechecking after running etc..