Europe - Sleeping in Heathrow?

I thought I'd make a small MR through LHR when returning home for easter holidays. I would arrive at 22-23, and then catch the first morning flight again at 6-7. That means around 8-9 hours in the airport. Do I really need a hotel for that short time? Does anyone have experiences of sleeping there? I've checked http://www.sleepinginairports.com already, but would appreciate advice from here as well.

Thank you for any advice!

You will probably be turned out, I'm afraid.The BAA is very strict about this.