Thanks for the feedback. I didn't want to cheap out too much on it, which is why I placed a spectrum, from the model that is on the Screwfix website, to the higher priced Heckler Power product. As I'm not an avid power tool purchaser, this was the first place I thought that I would check.
Having read through the comments, I think it's safe to say that I will either rent a chainsaw, or go down the route of recip saw. I'll have to have a look around to price some things up. I may possibly be back if I need to ask any more questions.
Thank you for the help!
I'll keep your all updated with the progress of what I'm choosing & what exactly the garden ends up looking like!