I need to put up a couple of things like a towel rail and a curtain rail in my son's flat. The wall seems to be plasterboard and behind that there's about a 20mm gap and then I think it's breeze block. I got a pack of plasterboard plugs which need a 6mm hole and have a sort of double prong which opens up behind the plasterboard.. The pack says they are for light use and I'm thinking they might not be up to the job. I've seen some bigger fixings which have a very big spiral thread which are screwed in. Would they be stronger? Or is there any other recommended way of fixing things?
Thanks
John