The court accepted that OP thought it was an intruder in the bathroom - that's why the decision was not one of murder.  It's no point arguing that the verdict was wrong unless or and until an appeal against it is made - the same argument as in the Ched Evans case.

On that basis the sentence would have been the same had it been an intruder.

We do not have the same perception in this country of armed intruders entering our homes as they do in South Africa where it would appear to be relatively common.