Trying to fix holes drilled too big between plasterboard and... brick?

[hamzahc]

Hi all - first time posting so hopefully this is the right place! I'm trying to drill some holes (just moved into new rental property) to mount our TV. I initially drilled smaller holes but realised there was plasterboard and then an air gap and then what appeared to be brick or mortar? I instead went to get some specialist plasterboard plugs that required a 13mm drill bit so now the holes are much larger and I can see through the hole that the gap between the plasterboard and whatever is behind it is too small for the "wings" of most plasterboard anchors to fit through (I had bought Snap Toggles ones but these definitely won't fit.

I'm now unsure what to do next. Should I fill in the holes and try again (is this safe to do? What should I use to fill them in?)? Or is there some sort of special plug I can get that's extra long to fit through all the plasterboard and deep enough into whatever is behind it. By looking through the drilled holes I can see at least a couple of them are definitely red brick, but the others look more sandy coloured (still solid when pushed with a screw driver though). It's above what used to be an old fire place (photos included). The plasterboard appears to be at least 15-20mm thick with then a small air gap and then it goes into whatever the solid material behind it is.

Any advice would be appreciated, this is day 3 of me trying to get what I thought would be a simple job done :


Ignore the patch jobs and the other large hole, these were left by previous tenant.

 

[martygturner]

corefix

 

[hamzahc]

corefix

Should I fill in the holes first with something before trying corefix? I guess so since the corefix look like they need 10mm drillbits and I've drilled at the least the plasterboard with a 13mm?

 

[jj4091]

Why can't you drill into the old chimney breast then use longer screws with Rawl plugs or similar secured into the bricks rather than the plaster board. You would fit the plugs loosely to the screw end then guide then into the hole. Tap the plugs home then remove the screws & fit the bracket, If you need to fill other holes for cosmetic purposes then any filler will do. Alternatively but more expensive short. window anchors