I Have Good News And Bad News
From The Lost Media Wiki
I've found an old recording of the special on this eBay listing, but the bad news is that not only is it a Betamax tape, it's cost's almost $50 to purchase, and the first 5-6 minutes are missing from the special (but the remainder of it is available, which includes the commercials as well) https://www.ebay.com/itm/TV-recorded-Betamax-Return-of-Bunjee-River-Mystery-movie-cartoon-Lost-Media-L11/133355381458?hash=item1f0c99a2d2:g:69oAAOSwlsteQ36i