I assume you are mentioning the British Battle Dress Blouse, for there was never a 'combat blouse': combat uniform coming in later, and with a jacket rather than a blouse.

The blouse was and is very smart when worn with the kilt, and there is a famous picture from the Battle of Arnhem [1944] showing an officer wearing such a combination.

Variants of the blouse appeared as mentioned in the form of the 'Ike Jacket' and it was also copied by the German Army.

The drawback being that to look smart it must be a perfect fit, and pressed: too a belt is advised.

The regimental tailor would adjust the issue blouses to fit the ordinary soldiers and officers would have theirs tailored.

When the battle dress uniform was discontinued in favour of service dress for walking out, and combat kit for active service: many of the soldiers complained because they felt that battle dress was smarter and more military-when worn with studded boots/gaiters and belt.

James