export quicktime h.264 increase bit rate

Hi
I am exporting TV commercials as QT H.264, but i have been advised by the stations to increase the bitrate, I currently have it on best quality, is there anyway to increas bitrate?
The only other accepted formats in Australia for SD are ProRes 422LT or 422HQ and Mpeg2 program stream, neither of which are available on Resolve 12.5 (that i can see, am I correct and will that change with 14.
I am on windows and using studio

thanks,
Nick

I tend to only export out of Resolve uncompressed or DPX Image Sequence then use dedicated software to create deliverables. My current goto is Wayne Norton's Convert v4 from HDCinematics.com

My workaround on Windows would be to export in DNxHR 444 and then use something like Adobe Media Encoder for the H.264, which will give you full control of many different parameters.