Nottingham Interspace tonearm help please

Hi

I'm having difficulty finding any clear set-up instructions for this arm. To be specific, there is a small grub screw on the left hand side of the arm base, towards the rear of the lift/lower section - does anyone know what it does?

Also, I can adjust vta from the arm base screw on the right hand side but I can't seem to find any way to adjust the lift/lower range (currently it takes an absolute age to drop because it starts off so high!)

any help appreciated.