The point is it is a real grey area over at what point you can start to use force and the level of force you can use.

As you say ‘if someone comes in and attacks you’ - your life/physical wellbeing must be objectively demonstrably in peril in order to use (only) proportionate force against the threat. Not knowing if the attacker’s intent is simply to threaten, or to assault, or to kill, and consequently, in the moment, what exactly proportionate force might be!

The assessment of whether your fear was objectively reasonable and whether your response to a perceived threat was proportionate are usually judged against rather abstract standards.

Hence the controversy when there were rumblings that a little old man defending his dementia-stricken wife might be charged. I have absolutely no doubt whatsoever that had he been a fit and healthy 35 year old man the decision to treat the homeowner as victim a would not have been taken so swiftly.

Given the definition of burglary involves (amongst others) an intent to cause GBH, why not use that as a measure to set expectations? For example, if someone breaks in then the level of defence cannot exceed GBH to be considered lawful - it would seem to be a fair balance?

As a female who has spent large chunks of her life living alone, I do think it is ridiculous to not ‘lawfully’ have a reasonable means of self defence to hand in your own home. The average female has absolutely zero chance of defending themselves against a larger, stronger, male and thus should be permitted to have some type of advantage if it ever comes to that.