2-Gang Patress Box Spacer

This is a spacer for a 2-Gang Patress box. There's a 1-Gang version lurking here: https://www.thingiverse.com/thing:4018006

I was fitting some controlled sockets and a couple of my patress boxes were too shallow; hence the need for a spacer (easier than chopping out the brick for a deeper patress box).

Yes, I know you can buy these for not-a-lot from a DIY store but I wanted black and they're not so freely available.

The outer dimensions (149 x 89mm) are for an Energenie/MIHome 2-Gang N