The 1U is worth getting for the dual INPUT and OUPUTs. The outputs are a nice way of interfacing with the rest of your studio. It takes the question of "can I connect this to that" and puts it to bed. You seem to have a nice budget for gear. So I'd get that and be done with it.
-- Ronin1973

Thanks Ronin, yes you’re right. It’s only £30. I was just wondering if I was pretty much replicating the functionality of my doepfer mixer though . The workflow would then be 4 mono inputs to doepfer mixer which are then connected to the mosaic 1u which is then sent to the uad Apollo and then out to speakers.

If the mosaic has some special auto reduction to line level built in then it’s a no brainer, but right now I’m assuming it’s just a manual gain stage. I’ve still not heard back from mosaic