Given the extreme intensity of certain battles, such as the Normandy Landings, were soldiers given time to rest/take stock before going back into action?
I guess my question is based around the welfare of the troops who had just survived an unbelievable battle and if they were straight back into action or not. Thanks.
No rule of thumb on this can be applied to all situations in WWII.
Ideally, units that sustained heavy casualties would go into reserve. This would allow men to be promoted into vacancies caused by casualties and new replacements to be integrated into the units and get to know their comrades and superiors. Additionally, it would physically allow the men to rest. Simple amenities like clean clothes, hot food, hot showers and adequate sleep in a bed could prevent or reverse combat fatigue cases.
However, if the tactical or operational situation required it, even after heavy casualties units would maintain their place in line or continue their attack. The U.S. Army in WWII was resigned to suffering significant casualties in their operations, at least by today's standards.
This second option is what happened to the main assault units at D-Day. For example, the 116th Infantry regiment which suffered the most casualties on 6th June at Omaha beach (along with the 16th infantry) was in action the following day, 7th June attacking to expand the bridgehead, clear up pockets of enemy resistance and relieve a pinned Ranger detachment at Pont du Hoc. On the 8th and 9th of June, the 116th regiment continued to go on the offensive to the west of Omaha beach. From June 9th-11th the 116th Infantry was still in the line. Finally it was placed in corps reserve on June 12th, although it was still available to repel counterattacks. After one day's rest, they resumed their attack in an "easier" section of line. Then on the 16th June the 116th became part of the push to take St. Lo, which would take them an entire month to achieve. This effort, 10 days after Omaha beach, so displeased the 116th's Colonel that he told his subordinates:
If you allow your unit to bunch up behind a hedgerow and wait for hours you are only playing into Jerry's hand. He will move around where he can enfilade you or drop artillery or mortar fire on you .... It is time to get over the jitters and fight like hell.
This speech, perhaps indicates that the 116th regiment was perhaps somewhat run down in morale after their first week and a half in Normandy.
The 116th is a bit of an outlier in that Normandy and D-day were some of the most intense fighting of the war for the U.S. Army and the logistical bottleneck of the beaches meant that the U.S. Army had to push the units that were landed harder than normal. However, it wasn't THAT much of an outlier. WWII infantry units were expected to take heavy casualties and keep fighting. Putting units in reserve was desirable and increased their effectiveness, but the U.S. Army typically put pressuring the enemy above maintaining maximum effectiveness. Tired troops had to keep fighting.