Hello,

I am new to development on Linux and I am struggling to understand what packages I require to get a working c++ compiler.

After searching the software center for gcc I see various packages which all have the same description yet all vary in size quite dramatically.

gcc - 9.2.0 (166.4Mib)
libgcc - 9.2.0 (4.3Mib)
g++ 9.2.0 (25.0Mib)

Could anyone assist me in getting the correct packages?

Thanks.

If you are going to compile then start with this one:
sudo eopkg it -c system.devel

kirkkaf
There are all the development tools for building packages. You can use eopkg info for more info about a package or components.

$ eopkg info -c system.devel
Name: system.devel
LocalName: Base development tools
Summary: Base development tools
Description: Development utilities - base system
Group: system
Maintainer: Name: Solus Team
Email: root@solus-project.com
Packages: abireport autoconf automake bash-completion-devel binutils bison bison-devel 
catbox cmake dbus-devel diffstat diffutils expat-devel fakeroot file-devel flex flex-devel 
g++ gcc gettext-devel gfortran glibc-devel gmp-devel gobject-introspection-devel intltool 
libarchive-bin libffi-devel libgpg-error-devel libgudev-devel libtool-devel libxml2-devel 
linux-headers m4 make meson mpc-devel mpfr-devel nano nasm ncurses-devel openssl-devel 
pam-devel patch pkg-config polkit-devel python-devel quilt readline-devel systemd-devel 
texinfo util-linux-devel xz-devel ypkg zlib-devel

See also here