Yes, thank you.
Not counting the Guards and Foreign Regts., there were 55 infantry battalions with Wellington's at the start of 1813.
Establishments for regiments:
1,210 men - 1 [1/43rd LI]
1,208 men - 2 [3rd Battalion and a single regiment]
1,200 men - 8 [first and third battalions]
1,010 men - 3 [first battalions Rifles and LI]
1,008 men - 11 [first and second battalions]
1,000 men - 13 [first battalions]
818 men - 2 [first battalions of Light Infantry]
808 men - 6 [second battalions and one single regiment]
800 men - 2 [first battalions]
608 men - 3 [all second battalions]
606 men - 2 [6 companies of 1/95th & 2/95th]
600 men - 1 [2/38th]
505 men - 1 [ 5 companies of 3rd 95th]
1/1st Foot Guards 1,630 men
3/1st Foot Guards 1,350 men
1/Colm Foot Guards 1,200 men
1/3rd Foot Guards 1,200 men
All King's German Legion Battalions were set at 1,000 men with the Brunswickers at 1,208 and the Chasseurs Brittaniques at 1,440 men
Royal Horse Guards 4 Troops - 300 men
All Dragoon Guards 6 Troops - 480 men
All types Dragoons 6 Troops - 480 men
[Life Guards not given, imagine close to the number for the RHG]
It does not appear that any of these regiments had depots or home battalions in Ireland.
As you say confusing. Perhaps the establishmentss were also partly due to the fact that certain regiments attracted more recruits than others and this was taken into account?