When I heard it was in pounds I'll admit to a brief flash of envy. (Though $550 a day would still be, erm, rather substantially more than Japanese salarymen my age get.)
$68/hour is less than my mechanic charges. It's not a bad living, but for a feast-or-famine consultant supporting a family as a sole breadwinner, assuming 70% utilization, it's a gross 95k salary, from which you subtract self-employment tax.