Installing a radiator into a plastered wall - Lots of problems. Help!

[Ahleckz]

I had some plastering work done a few weeks ago and have tried putting my radiator back on.

Originally, I've tried using screws and the brown rawl plugs. This worked, until I was tightening up the pipes and the hole gave way and the screw came out.

Today I went to B&Q and bought proper radiator fasteners (the ones that you screw in, and then screw out which allows the metal plug to expand outwards and 'hook' into the wall) but the same story happened.

Tried then screwing the bracket in through some wood, which was attached to the wall to give it some more stability but that didn't help.

So, what on earth do I do? There doesn't seem to be any immediate brickwork behind the plaster for the top two holes - just seems like a void and then some concrete. Bottom two seem to have red brick but too far away for the hooks to hook into.

So, any ideas? Or, failing that who would be the best tradesman to get in to fix it up? Getting awfully fed up of not having a radiator in my living room.

 

[Ahleckz]

Gex, they are the 'hook' things I was trying to describe.
I don't even know what it is. There's brick work maybe 6cm back but before that it just seems to be loose plaster, not even sure if there's even any plasterboard on it.
Think it was a bit of a botched plastering job to be honest.

Going to need some pretty long screws and rawl plugs, not even sure if they make plugs that long! Didn't see any huge ones in B&Q today.

 

[Ahleckz]

Use these for the top two if the distance between the plasterboard and brickwork is too long.

http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9372165&fh_view_size=10&fh_start_index=40&fh_eds=%3f&fh_location=%2f%2fcatalog01%2fen_GB%2fcategories%3C{9372210}%2fspecificationsProductType%3dwall_plugs&fh_search=fixings&fh_refview=search&ts=1266528103645&isSearch=false

Just pre drill a 6 mill hole first then wind them in.

So drill a 6mill hole, and then put them in so the heads will be 6 mill in the wall? Or am I missing something...
They look like what the radiator was originally attached with. How does that work? I thought they were just another form of plug, which haven't worked so far...

No I would use these, these are better (take more load)..

http://www.axminster.co.uk/product-Axminster-Boardfix-Cavity-Fixing-21598.htm

when you screw them in, it pulls the 'plug' back towards the back of the plasterboard and forms spider legs. pretty tough. i can hang from two of them (12odd stone)

they dig into place with the two teeth as well so don't spin etc.

See above, tried them. The wall just didn't support it. Hole collapsed downwards...

 

[Ahleckz]

I'm actually thinking there was something wrong with either the hole, or the screwing. I just checked the hook things, and the problem actually lies there it'll seem. Didn't do any diagnosation after it failed for the 3rd time just threw it all in a corner and had a drink.

Is this a problem with the hole, or the person holding the tool? What could cause this to fail?

You can see the proper fixing at the back and the one that failed at the front - did I over screw or something?

 

[Ahleckz]

Those spring things seem like they could be the answer...

Don't really want to get the professionals in if I can avoid it, may as well keep making holes until it works or I need to get a new plasterer around!