You can but you have to change it from a 2 module to a 3 module. You will need to use the following part numbers to fit a normal RCD in the top section.
Â
56E3 -Â Mounting Back Box, 3 Gang

Â
56CB4 -Â Mounting Cover Kit, 4 Module, Less Neon

Â
56SO315LE -Â Socket Outlet Srf 3 PIN 15A Less Enclosure

For further information please visit:
https://www.clipsal.com/products/detail?CatNo=56E3&itemno=56E3-RW&backto=/search?q=56e3&tab-document-1=0
https://www.clipsal.com/products/detail?CatNo=56CB4&itemno=56CB4-GY&backto=/search?q=56CB4&tab-document-1=0
https://www.clipsal.com/products/detail?CatNo=56SO315LE&itemno=56SO315LE-GY&backto=/search?q=56SO315LE&tab-document-1=0