rear = 265/35/19
fronts= 245/35/19
wheels are rotas
Maybe a wider tyre on the rear then would help, 275/35/19 is the norm but guess you've gone for stretched due to offset of the wheels maybe, though I'm no expert when it comes to it.
tbh iv only had the car since june and when I had the service done i just asked them to replace with the size already on .didn't know they were stretched if im honest .
so with them been on the car only a couple of weeks i dont really want to be replacing tyres yet