Reaching awkward screw on shelves when fixing to plasterboard Information, help and advice on many architecture, self build and design problems and issues

[CallieSylvia]

I bought some shelf brackets to hold a heavy sound bar and am trying to install heavy duty plasterboard wall plugs with 4.5mm screws. They need to be screwed in tightly obviously but the shelves have a design flaw where I cant get close enough to screw in one of the fittings - help! I dont even think an offset screwdriver would fit