I decided to install this bollard at the end of the garden near my pond but 70w SON is a bit too bright for this application.

Top photo shows the original control gear which is standard Vossloh-Schwabe fare for 1 x 70w SON lamp and interestingly has taps for 220-230v and is wired for 220. The ignitor and PFC are on the reverse of the geartray.

Bottom photo shows the Philips ballast and ignitor/stabiliser unit fitted for 1 x 35w SDW-T "White SON" lamp.
I mounted the PG12 lampholder in such a was as to ensure the centre of the arc tube is in the same position as the original 70w SON lamp.