I have a LCD mounted without using the joists or noggins, just straight into the plasterboard, using these.
http://www.screwfix.com/app/sfd/cat/...12229&ts=81338
If you place the mount on the wall where you want your TV and mark your holes, drill small pilot holes 3mm.
If they all go straight through into hollow section use the wall anchors, to use them drill a hole stated on the packet of anchors, push them into the wall and tighten, they mushroom out and press up against the wall.
If when your drilling the pilot holes you hit wood, drill and couple of pilot holes either side to make sure your not on the edge of the wood. If it's not on the edge of the wood you can just use a wood screws.