Bastard. I had doubts that I'd be able to open it, but tried anyway... 

So...
Replace the OE holder nut and nipple with these?
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=SSA00475
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=BRA00470
Or this?
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=BRA12111


So...
Replace the OE holder nut and nipple with these?
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=SSA00475
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=BRA00470
Or this?
https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=BRA12111