Oh, the glamour...

Work on my new kitchen is progressing - slowly. Today I ordered new worktops. They should arrive in about a month.
This means I will be without a kitchen sink till then. However, I don't have enough clean pants to last that long so am left with trying to close off the waste pipe so I can use my washing machine without flooding the kitchen - it was flooded before, which is why I'm fixing it up.
And so, after two visits to B&Q and twice picking up the wrong thing, I'm hoping it will be third time lucky when I try again tomorrow.
DIY? Wish I could afford to pay someone to DIFM.