Thanks Nick, I got lucky with Uranus. After I finished one image with Mars I just typed "Uranus" into the handbox and (for the first time ever) Uranus just appeared on the screen!
Normally I use my 8x50 RACI finder (which can just detect Uranus) and SkySafari on my phone to point at Uranus and then just slew around until it appears on the screen.