Yes, you're right, I love this movie, it's one of my favourite. Tension is high till the end...David Hemmings took part in very interesting movies in that period, culminating in Deep Red.
How long does your English dubbed version run for? 97'27" circa?
I've got an old Italian TV recording running for 101', a bit longer than the English dubbed TV rip shared at that place (96'45"), I guess that it's mainly due to the long end credits.
Is Made by the same director good as well?