Just a thought Sp0oner, but there are a couple of threaded holes on the forward-facing side of the top yoke, one on each side. I used one for my reservoir bracket but at the time reckoned they were probably there for mounting accessories.
Mine broke today, so no longer recommend it. ETA: Having said that they're sending me a new one as they said the failure was very unusual so I'll update when I've used the new one for a bit.
I'll vouch for the RAM mount kit. I use their hardware for anything I need to mount to the bike; phone/sat-nav/GoPro/etc. Been using this for when I need the phone up front for yonks (and multiple different phones) and can't fault it: https://www.ram-mount.co.uk/device/gps-mounts/aqua-box-medium-size
Finally got all mine set up today and very pleased with it although not been out for a ride yet. Not cheap at nearly £100 for the bolt, arm, quadlock mount and quadlock phone case.
