Thanks all.
I ended up picking up the folding Bluetooth keyboard from EC Technology. I've written up a review below and I'm currently test driving the Microsoft UMK recommended in this thread and I'll share my feedback in a bit.
https://forums.macrumors.com/threads/1843445/
Is this EC still holding up to being a good portable keyboard? The ThinkOutside ones were great as they had laptop sized keyboards but folded up really small. The travel and typing experience is really important - given i'm not the worlds best typist anyway..
If you have any comparisons against the Apple wireless keyboard, which I'd choose if it folded (!), that would be appreciated.
Yes, this is still my go to mobile keyboard and its working great for me, so much so that two work colleagues have since purchased one. I had two previous TO keyboards, the black one with four sections that folded up but needed to be used on a flat surface and the later aluminium one that had two sections that slid and folded out. The EC model is probably similar to the latter TO aluminium keyboard. I've tried a few mobile keyboards of late and this is my favourite of the foldable ones.
I compare the size against the Apple wireless keyboard in the video review posted in this thread.
Thanks; I had both of those as well. Will watch your video review later but think I'm sold!