This is the second performance from the "Modular Meets the Elektrons" event in Leeds. The event was run by Ben "DivKid" Wilson, if you haven't checked out his YouTube channel be sure to head over there to check out the full performances.
Bitloader is the band name of Zoe and Nina of Transistor Sound Labs. In this performance they were using three of their Stepper Acid modules to make three different 303 style lines.
They then had some drum loops playing from the laptop and a keyboard set up to control some soft synths.