Hello everyone,
while recording my submissions for VC5 I’ve had a problem with finding a dark background, or even a suitable piece of dark cloth to hang behind me - it seems quite a number of people have this issue. I’ve resorted to buying large-sized black garbage bags, cutting them along the side to form a sheet of black plastic and taping it to the wall. It worked wonders 
- it looked nice, the bag easily fills the entire frame and they are dirt cheap - try it out 
I hope this helps anyone who is still recording their submissions. Good luck!