Help locating a copy of oppurtunty knocks final ep from 1978

[Baloo1986]

Hi this year my grandmother is 90 she loved hughie greene and opportunity knocks in 2003 she had a vhs of the final ever episode when she taped it off challenge tv now the vhs is missing and I am desprete to get her a copy sorry about the spelling I need it on dvd to buy off some good price paid I have tried YouTube no luck some one must have a copy please help