So I recently recorded some video in 4K HDR10 and it’s saved in HEVC / H.265 format in MP4 container. I use Premiere Pro CS6 for my editing, which should be fine for the 4K part but it cannot import H.265. What is the best to get around this? I assume converting to H.264 but any converts I can see look dodgy or scale to 1080p, so I’m a bit stuck! Many thanks, help is greatly appreciated!
I suggest you look for a tool that can convert your files to ProRes, DNxHR or a similar intermediate format. These formats are much better for editing than another capture/delivery format like H.264. Typically you would need to purchase a tool to transcode the media, unless the software for your camera can do it (e.g. Sony cameras).
If you want to avoid spending any money, you could try transcoding to 10-bit H.264 I-frame only. Handbrake or FFmpeg can do this.
However, your bigger problem will be editing the file in Premiere. HDR10 had not been invented when CS6 was released, so your colours will be wrong. If you want to work effectively with this media, I think you need to move to more modern editing software.