There are several translations available of
1 Enoch (of which chapters 37-71 are the Similitudes of Enoch). By far the best and most up-to-date is:
George W. E. Nickelsburg and James C. Vanderkam, 1 Enoch: A New Translation (Minneapolis, Minn: Fortress, 2004) (Amazon.co.uk link here)
If you are interested enough in the Pseudepigrapha to be following this course, this book is a worthwhile investment and I encourage you to buy a copy. (Students in the course: there are copies on short loan for this module in the libraries.)
The translation by E. Isaacs in the Charlesworth OTP is conveniently available, but it is now quite out of date and thoroughly superseded by the new translation. An old (1917) translation by Charles is available online, as well as an even older one (1883) by Richard Laurence. Both are extremely out of date. If you are limited for some reason (e.g., being stationed at an Antarctic base) to online resources, use the
Charles translation. But if you have access to Amazon, order the Nickelsburg/VanderKam translation (and maybe even buy a second copy to donate to your local library).