Back box – https://www.bemco-knx.co.uk/jung-british-standard-flush-box-metal-p/bs6042m-40.htm
Insert - https://www.bemco-knx.co.uk/506u-switch-insert-1-pole-2-way-p/506u.htm
Frame - https://www.bemco-knx.co.uk/jung-ls981ww-1-gang-frame-white-p/ls981ww.htm
Rocker - https://www.bemco-knx.co.uk/jung-1-gang-rocker-p/ls990ww.htm
Back box – https://www.bemco-knx.co.uk/jung-british-standard-flush-box-metal-p/bs6042m-40.htm
Insert - https://www.bemco-knx.co.uk/jung-2-gang-switch-insert-1-pole-2-way-p/509u.htm
Frame - https://www.bemco-knx.co.uk/jung-ls981ww-1-gang-frame-white-p/ls981ww.htm
Rocker - https://www.bemco-knx.co.uk/2-gang-rocker-white-p/ls995ww.htm
(Same Frame and back box as above)
Insert - https://www.bemco-knx.co.uk/rotary-dimmer-universal-led-p/1731-dd.htm
Dimmer (instead of rocker) - https://www.bemco-knx.co.uk/centre-plate-with-knob-p/ls1940ww.htm
Double frame so you can mount two sets of switches together — https://www.bemco-knx.co.uk/2-gang-frame-p/ls982ww.htm