I used to pick it up on Kodi but it wasn't Mrs Clive's cup of tea. I haven't noticed it on Netflix. You might be able to get it on Now TV which includes Sky Atlantic for around £8 a month and you can unsubscribe at any time. They have a lot of Box sets and Game of Thrones just may be included. I think you can get a 14 day free trial.
I think Sky own Now tv so I would imagine you can get GOT on it. Definitely not on Netflix.
I tried Prime (inadvertantly
) a few years ago and found the quality of the stream quite poor at times, whereas Netflix is usually really good if you have the HD or UHD subscription. I love GOT myself, but opted for the disc box set route.