Discovered via a WW2 blog site and the first article concludes:
During the battle for Ortona, the Canadians innovated, improvised, and successfully exploited the effects of their personal weapons and supporting arms under largely unforeseen circumstances. Following a week of fighting in Ortona, the Canadian division became Eighth Army’s acknowledged street-fighting experts. In serving notice upon the Allies to expect further such battles, Ortona also carried implications. In Britain, armies composed mostly of untried formations waited to open the main ‘second front’ in northwest Europe, where they could expect an equally stubborn and desperate German defence. Ortona therefore merited close study, and received it from training staffs throughout the Allied armies.Canadian assessments figured highly, and they remain an instructive case study in the evaluation of battle experience.
Link:http://www.journal.forces.gc.ca/vo8/...oderso-eng.asp

Amazing that the Canadians learnt so quickly.

The second article in part explains the learning:
The Canadians, recognizing that following standard doctrine would result in heavy casualties, swiftly indulged their tactical creativity, devising methods to make them more effective. The most notable of their solutions was the advent of mouse-holing, whereby soldiers would blow a hole in the wall separating two back-to-back buildings, either with explosive charges or the man-packed PIAT (Projector, Infantry, Anti-Tank) launcher, in order to avoid entering the streets and exposing themselves to fire. This inventiveness gave the Canadians a substantial advantage at Ortona, as the German forces were not only surprised by the switch from conventional tactics, but failed to adequately counter the improvised warfare, instead having to rely on conventional counterattacks, usually under the cover of night.
Link:https://www.seaforthhighlanders.ca/stories/470

The original website thread has other links, which include videos.
Link:http://ww2talk.com/index.php?threads...-ortona.55293/