I don't know where your Dad took his test obviously but I took mine over 30 years ago and then took my motorcycle tests just three years ago and I'd say that they were similar although the fear of not passing was greater the first time around.
You didn't have the theory test on the computer back then, true, but you had to know the Highway Code back to front because you were still tested on it, maybe only two or three questions but you had to be word perfect and they could be obscure. I honestly wouldn't say from then to now one was easier than the other.
North Cornwall in the mid 1960s. I just spoke to him about it earlier this morning, he said they probably asked him some highway code questions but he couldn't remember. He just remembers being asked a few questions about the car and as he'd grown up building and riding motorbikes and it was my Nan's car he was driving and he'd taken that engine apart and fixed it a few times, he remembers talking to the examiner about that and that which was probably good enough for him.