A telescope for GCSE Astronomy is a nice to have. It is certainly useful to help record observations. We advise checking out the stock on our sister site.
Remember we also have access to the Faulkes Telescope for observations as well.
The best kind of telescope however is one that you use. Starting with a small refractor and building up is best. Even a small telescope (70mm or so) will show the craters of the Moon, Jupiters belts (and Galilean moons) and Saturns rings. Even some detail on Mars. Always start with binoculars though and learn the sky first! 🙂