I'm also from the IoM, and my grandparents told me about the tragedy as it happened just before I was born. When they took me to the rebuilt Summerland in the late 80s, I remember that they always made sure we knew where the fire exits were.
There's a big memorial service planned this year, but it's only really in the last few years (since Grenfell I think sadly) that it has become more widely talked about. Absolutely tragic, and yes, lessons should have been learnt from Summerland which weren't.