I kept a diary throughout the 70s.
Usually listed the guests on the Parkinson show.
For this date I have the guests recorded as Roger Vadim, Twiggy and Spike Milligan.
I have no mention of Roger O'Toole. I was 15 years old so it's hardly something I would have written by mistake and I wouldn't have any incentive to deliberately record the wrong line up!
I also wrote that the show was 'good' but that it ended 'very weirdly'.
Unfortunately I didn't say why.
That's why I tried to look it up on line but found this IMDb entry instead.