It's ok to use cling film sometimes. Wherever you are in the world the conditions might mean that dough left out for a while under a cloth dries out on top, or un-avoidable draughts create a thick skin on your dough. Whatever the reason an air tight seal might help out. Here's my advice on using Cling Film properly and how to keep it to use over and over again.
Bread Tip 104 - How to Use Cling Film PROPERLY and Re-Use it After