It's very difficult to drive with the other wheel on, steering feels heavy and sluggish, and there's vibration there all the time, worsens when braking. The 19" beside an 18" is close in diameter but the 19" is slightly larger diameter. It's the only thing I can think of!

I've been keeping her about 80kph normally and no more than 100kph on motorways but it's definitely noticeably not driving/handling right! I'm praying it,s because the different size rim and tyre. I was meant to get my own rim back yesterday but they hadn't it finished and I'm working the weekend so need the car!