Deciphering Artillery Markings. Canadian?

[JohnC]

I'm spending some time this wet Sunday attempting to decipher the markings on a trench map, below. I could use some help please.

The map is made of joined sheets 51B SE and 51A SW, area north-west of Cambrai immediately after the crossing of the Canal du Nord, October 1918. There are two sets each consisting of four artillery positions, numbered 96, 140, 326 and 337. The first set is around Haynecourt, each position marked with a coloured azimuth sector (red, blue, yellow, green) and a penciled range arc at 10,000 yards. The second set, I assume the same unit few days later on, is in the Sancourt-Blecourt area, azimuth sectors marked quite fancily in pen, and range arcs marked at 9,000 yards. The centre line of all guns points north-east, bearing 70 degrees. 

This area was the junction of the British 11th Division and the Canadian 1st then 2nd Division. There are more markings well into the Canadian zone, so I'm guessing that the gun positions represent units of the 2nd Canadian Divisional Artillery. There's a red line between Hem-Lenget and Paillencourt, which is where 2nd Div crossed the Sensee Canal on 17th October. Nearby, there's a coordinate box 'FAB' east of Wasnes au Bac containing MGs. There are also numerous HQ markings, including 5CDA at Eswars. On the cover in pencil is 'HLO'.

My guess is that this map relates to the action of 2nd Canadian Divisional Artillery, perhaps 5th Brigade, at the advance to and crossing of The Sensee. After all that preamble, my questions are:

1. What do the numbers 96, 140, 326 and 337 relate to? I can't find batteries with those numbers. Are they individual guns?

2. Is it possible to deduce the type of gun? The distance of 9,000 yards seems to be within most type's range.

3. Any ideas about 'HLO'? Howitzer Liaison Officer?

All suggestions welcome, thank you in advance.

John