Hi there, I don't have any direct experience but Whitecar (Whitecar | Car Hire Beyond Expectation | Tesla Rental | UK & Norway) have an excellent reputation and one of their bases is in Edinburgh. I thought I read that Enterprise have started adding Teslas to their fleet although I just had a look at their website and didn't see anything about it there. It would be worth asking over on the UK forum as you'll probably get more locals reading your post.
Scotland is a great place for EV driving as there is an extensive (and for the most part free-to-charge) public network if you want to travel beyond the reach of the Superchargers. Good luck planning your trip!