I really wanted to go to the IOW Festival, but a tad too young, I did a lot of one day festivals around that time and saw some big names. Leonard Cohen didn't resonate with me until a few years after that time.
There's a place on the IOW called Dimbola Lodge which is or should I say was open to the public. When I went it had a great photographic exhibition of that 1970s concert. Although browsing the pictures I found my more mature self pondering the state of the toilet facilities, I can remember missing whole acts during the queueing for those when I went to open air concerts at the Oval and Crystal Palace. Sigh! heady days, that IOW concert was the concert to end all concerts I imagine, unless of course you happened to go to Woodstock!