http://www.abs.gov.au/ausstats/[email protected]/Latestproducts/6530....
6M or so people receive some kind of welfare benefit for a total of 77.8B dollars. Total expenditure on welfare in Australia: $154B (latest budget figures).
That's nowhere near a 5x overhead, but it is pretty damn inefficient.
The fact is the Australian government spends in the ballpark of $2 for ever $1 of benefit handed out; whether it's $1.80 or $2.20 doesn't really matter -- it puts some actual figures behind the concept of simply giving out a basic income (versus trying to figure out who gets the benefit, means testing it, and so forth).
Australia's unemployment rate hasn't changed much over the period 2009-2014 (it was shielded from the great recession by commodity prices).
"In 2010-11, Australian Government and state and territory government welfare spending was estimated at $119.4 billion - $90 billion (75%) was in cash payments (including unemployment benefits) and $29.4 billion (25%) was for welfare services."
So to make your case you'd need to dig up figures about how much the administrative overhead related to the cash benefits is.
The principal cost is staffing for the vast number of people needed to means-test, scrutinise, shuffle paper and rubber stamp things - were you to dispose of much of this apparatus by going for a straightforward "everybody gets £x/month", your efficiency would rocket.
That is, of course, if the actual main cost isn't money being siphoned off into politicos pockets.