In the UK version you are far less likely to have two armed men attempting to break in in the first place. But anyway... even if they do, you are entitled to use reasonable force. In other words, whatever force is necessary to defend yourself, even if that results in a fatality. Couple of cases where people have been aquitted in exatly these circumstances
here.
Unfortunately that CATO report cherry-picks cases to justify its stance and then doesn't give all the facts. As an example, the Tony Martin case: he was jailed not for defending himself, but because he shot the burglar in the back as he was running away, with fatal consequences. The court found that to exceed the definition of reasonable force.
The same applies to the Munir Hussein case, which is another one often misquoted in these discussions. He was jailed for chasing after burglars, calling someone to assist him, then when they caught the burglar, hitting him on the head with a cricket bat repeatedly, causing brain damage. Again, the court felt that by pursuing when he was no longer in danger, he had moved from defending himself to seeking revenge.
BBC News - Q&A: What is 'reasonable force'?
Both these cases are what's called the 'castle defence', which is when the householder moves from defending themselves as a priority, to inflicting violence due to the initial motives of the burglar. There are plans to make this legal in Ireland. It'd be interesting to see what happens, but while our own English law is far from perfect, I think castle defence is a step too far, as it'll lead to a rise in vigilante style attacks using it as a cover.
Ironically I spend a lot of time on a mainly US forum where people continually post about the gun collection they need to make them feel safe in their own homes, and the heavily armed gangs that pose such a problem in their neighbourhoods.
There is an ambiguity in the law over self-defence, and a lot of people don't really understand quite what their rights are. There's a guide here from the CPS:
Self Defence: Legal Guidance: The Crown Prosecution Service
As for the case in Texas, I just think it's sad. I'm pleased, obviously, that no harm came to the woman and kid, but saddened by the fact that it happened at all. And having lived in quite a few societies awash with guns, I feel considerably safer living in one which is not.