1000$ ~= 640 pound ~= 800 euro - that's what a 'regular' consulting firm (i.e. not big four who will charge double that, but medium sized regional players) charged for a fresh out of school grad, in the UK. It's only slightly more than what a secretary in a law firm costs (although to be fair, they don't get billed out by the day). It's roughly what the most simple engineering studies are billed at ('calculate required dimensions for this steel beam with uniform load' - i.e. the sort of work they let (supervised) interns do, structural engineering 101).

Really, everybody reading this (yes also those in the UK!), if you are an experienced or senior software engineer and you're billing yourself out at these rates ($1000 a day), you're leaving money on the table. If the mentioned work is what I consider 'data science' (i.e., advanced applied statistics requiring fair amounts of high-end, performant software engineering), then $1000/day is really low if it's for anything more than what somebody can do as a weekend gig next to their day job.