Thanks.
I took 8 still images, 4 on the top row then lowered the gimbal a bit and took 4 more going back in the opposite direction. I then lens corrected all 8 in Adobe Lightroom and photo merged using the standard Lightroom tool - i'm pretty lazy in that respect. Nothing fancy and if it doesn't work I tend to move on ;-)
I used a lightroom preset to get the vibrance and saturation levels up and tweaked just a little bit.
The clouds look good but it does result in shadows across the cityscape so could have been better in that respect but then without the shadows they'd be no clouds and the sky would look pretty boring.