We all know that the Tans dished out some brutality to ordinary people, but the IRA were responsible for some appalling atrocities too, and this is a dimension of the conflict that Loach chose not to explore in his film. By all means see it, but do not suppose that you are getting a balanced historical view.

The Tans may have created some "resentment and hatred" but less than 20 years later that had evaporated as free Irishmen in their tens of thousands turned their backs on the IRA who were in alliance with Nazi Germany, and flocked to join the British forces to fight against them.

Re your experience with the British Army, it would be helpful to know if you were a volunteer with PIRA or related Republican group in the armed struggle.
As you keep telling us, the war is over now and you need not be coy or ambiguous in your answer.