I have to leave early/coming late?

That is also fine, we live in London and it is a busy city with a lot going on.  We recommend coming for the warm up though as this will prevent unnecessary injuries and help with your mobility.

Do I need to wear flip flops?

Yes they are compulsory when off the mats, you must not walk around off the mats barefoot (unless you are wearing "barefoot" flip flops/shoes If you don't have any you can buy flip flops here

Do I have to wash my gi after every class?

Yes as the gi's get very sweaty and must be washed after every class.  We recommend washing them at 30C with some antibacterial powder.