I'm old but not quite that old!
I just wanted to chime in to say that 23 is fast but not what I've seen to break 1.44. Every one of the sub 1.45 guys I've trained with have been able to run faster. Of course, there are a few that buck the trend and have a different way of getting to that time, but they are definitely 1500 guys with a strong middle 400. In stating that I have done it I was just letting the original poster that there is someone with actual experience trying to answer his question.
And as far as being funny, I like to see the names being thrown out, I have raced a guy or two that have been named. The UK guy just came in hot to the thread and that's the reason why people with me don't say who we are. there's always guys like that claiming BS.