It might be a loading mistake but it works.
Even the official Eurostar tariff table does not mention these rates but here we go: you can currently book one-way tickets on Eurostar for only 33 EUR or 29.5 GBP. Today is Aug 26th, these rates are available for trips starting in the last week of september 09 and onwards.
I just bought 4 trips, and I would try more if the Eurostar web site did not keep killing my session this morning.
Tales and tips from a real Eurostar Client 
Hi, I need a ticket to lille, to travel to Lille from london on 25/8/17 and coming back on 27/8/17. Please call me on 07405697174 or email me : felixdiv AT hotmail DOT com
Posted by tel: 07405697174 | August 18, 2017, 12:19 pm