On Friday, 11 October 2019 10:40:17 UTC+1, The Natural Philosopher wrote:
is there something like a clip-in plate
that will fill the space in the front plate?

https://www.electricalcounter.co.uk/products/151357156
https://www.screwfix.com/p/blank/8285P

screwfies do crabtree and wylex metal blanks if you prefer

https://www.screwfix.com/p/crabs/6141p

Owain