I thought it might be useful to add a bit more on the reductions seen in the British components of 21AG in the months following the Normandy campaign.
Infantry Divisions and Brigades
At the end of June 1944 there were eight British Inf Divs in theatre - 3rd, 15th, 43rd, 49th, 50th, 51st, 53rd and 59th. Of these, 59th (Staffordshire) Div, was among the last to arrive in Normandy, and it began disbandment in late August 1944. All of its nine Inf Bns were broken up, and its three Field Regts went to Army for a while at least.
49th (West Riding) Division was composed of 146, 147 and 70 Inf Bdes. The last of these left the Div in late August 1944 and was subsequently disbanded in mid October 1944. It was replaced by 56 Inf Bde, which had been an Army level formation prior to that.
147 Inf Bde had one Bn disbanded in Normandy (6 DWR) and received one Bn (1 Leics) from 162 Inf Bde as replacement.
With eight Inf Divs and one Inf Bde there were 75 Inf Bns on the books at the end of July 1944. With the reductions above that became seven Inf Divs with a total 63 Inf Bns. 13 Inf Bns were disbanded, with one one being directly replaced.
Armoured Divisions and Brigades
At the end of June 1944 there were three British Armd Divs and one Armd Div (Special) in theatre - 7th, 11th, Gds and 79th.
7th Armd Div had one Armd Regt (4 CLY) removed at the end of July 1944 and replaced by a Regt from the UK (5 DG, from 28th Armd Bde in 9th Armd Div).
11th Armd Div had its Armd Recce Regt (2 NY) replaced by a Regt from the UK (15/19 H, from 28th Armd Bde of 9th Armd Div).
There were four British Independent Armd Bdes in theatre by mid June 1944 - 4th, 8th, 27th and 33rd.
4th Armd Bde merged 4 CLY (from 7th Armd Div) with its own 3 CLY to form 3/4 CLY.
8th Armd Bde had one Armd Regt (24 L) removed at the end of July 1944 and replaced by a Regt from 27th Armd Bde (13/18 H).
27th Armd Bde was disbanded at the end of July 1944. All three of its Regts went to other Formations.
33rd Armd Bde had one of its Armd Regts (148 RAC) removed in mid August 1944 and replaced by a Regt from 27th Armd Bde (1 East Riding Yeo)
With three Armd Divs and four Indep Armd Bdes there were 24 Armd Regts on establishment. That reduced to 21 with the disbandment of 27th Armd Bde. One Regt was merged with another and two were disbanded. Two Armd Regts were sent from the UK as direct replacements (leading in turn to the disbandment of 28th Armd Bde and with it 9th Armd Div). Two Armd Regts already in theatre were transferred to new Formations.
79th Armd Div started the campaign with three Bdes, one RE, one Armd (Flail) and one Tank (CDL). The CDL equipped 1st Tk Bde was placed in suspended animation (disbanded) in late 1944. Two of its three Armd Regts were re-roled and re-equipped for special operations and the third (42 RTR) disbanded. 30 Armd Bde remained intact throughout the campaign. 79th Armd Div also added three Regts from other Formations (one each from 9th and 27th Armds Bdes and one from 31st Tk Bde).
Tank Brigades
Three Tk Bdes arrived in theatre during the course of July 1944.
6th Gds Tk Bde - no changes
31st Tk Bde - initially had three Regts on strength, however one of these (141 RAC) was detached and never fought as part of the Bde, becoming part of 79th Armd Div instead. Both 7 RTR and 9 RTR were posted to other Formations. HQ 31st Tk Bde became part of 79th Armd Div in September 1944 and administered a variety of specialised units. It latterly became a 'Crocodile' Bde and both 141 RAC and 7 RTR returned to it, along with 1 Fife & Forfar Yeo, the last unit from the disbanded 28th Armd Bde.
34th Tk Bde - had one Regt (153 RAC) removed in late August 1944 and replaced by 9 RTR in early September.
Overall there were nine Tk Bns on establishment at the end of July 1944. That fell two six Tk Bns during September 1944. Two units were redeployed and one was disbanded and replaced by a unit in theatre.
Late 1944 and early 1945
There was another round of changes in late 1944, with the arrival of 52nd (Lowland) Div during Sep-Oct 1944, which was offset by the departure of 50th Div in Nov-Dec 1944. Then at the start of March 1945 was the arrival of 5th Div from the Med. Also of note in late 1944 and early 1945;
7th Armd Div - 131 Inf Bde received two Inf Bns from 50th Div (2 Devons and 9 DLI), who replaced 1/6 and 1/7 Queens, who in turn joined 50th Div and returned to the UK..
11th Armd Div - 159 Inf Bde exchanged 3 Mons with 1 Cheshire from 115 Inf Bde
Gds Armd Div - 32 Gds Bde replaced 3 IG with 2 SG in late February 1945. Also 1 WG left the Bde and were not replaced (Sheldrake, is that when 21 Atk Regt RA took on its Inf role?)
115 Inf Bde arrived from the UK in mid February 1945.
116 (RM) Bde arrived from the UK in the latter part of February 1945. 117 (RM) Bde arrived after the end of hostilities.
More generally the reductions in Anti-tank and Light Anti-aircraft Regts in Inf Divs were built into revised war establishments particular to 21 Army Group. The Inf Div Atk Regt had an authorised strength of 718 all ranks in June 1944, with 16x 6-pdr and 32x 17-pdr guns, all towed. In October 1944 that became 646 all ranks with 16x 6-pdr and 12x 17-pdr towed guns and 12x 17-pdr SP guns. Finally in March 1945 that went up slightly to 656 all ranks, with 18 towed and 18 SP guns, all 17-pdr. Armd Div and Corps Atk Regts did not have new WEs issued. As mentioned earlier in the thread the two towed 17-pdr Btys in Armd Div Atk Regts were used as Inf. 75th Atk Regt in 11 Armd Div did not make that change until April 1945 though.
The Div LAA Regts had been increased by the addition of 20-mm armed Tps in early 1944, which pushed strength up to 1040 all ranks, with 54x 40-mm and 24x 20-mm pieces. As alluded to earlier the RA saw deep cuts in 21AG which reorganised all its LAA Regts, bringing strength down to 578 all ranks and 36x 40-mm guns.
That's all from a couple of hours with the wonder that's Joslen's Orders of Battle. I told you it was a big subject
Gary