I have been reviewing the state of the army recently and it seems a lot of good work has been going on. I'm particularly impressed with the 6th Brigade.
However, I noticed the artillery regiments are described as two batteries of six guns. What is the reason for only two gun batteries?
Army has been and is continuing to re-organise it's structures significantly over the past decade and will continue to do so over the next decade.
To answer your question specifically, an artillery regiment is attached to a Brigade and those two gun batteries per Regiment now support the two infantry battalions that exist per brigade...
Artillery has been reorganised with the introduction of the new M777A2 155mm gun, plus the digital fire control system, (AFATDS) the significantly greater use of smart munitions - Excalibur, SMART 155 and course-corrected fusing capability (GPS / INS guided fuses for standard 155mm rounds) plus the replacement of the 105mm artillery capability by 155mm capability across all Artillery Regiments.
Our artillery capability is not as big numbers-wise as it used to be, but it's far more capable and lethal nowadays.
Combined with the new mortar system we are acquiring, the vastly improved direct fire capability we have and will continue to improve over the next decade or so, plus the Tiger ARH, Army's fire support capability is in a pretty excellent place right now.
(On paper at least).