Discount Musical Tickets London

Discount tickets musicals London?

I am going to London in July and I want to see Les Miserables. I found two sites Discounttheatre.com and http://london.broadway.com/.

I was wondering if these were safe to buy from? I found really good seats there, but don’t want to be scammed.

If they are not safe, where is the best place to get cheap tickets?