Change Deleted Members Display Name

I've recently upgraded a board from 3.4.8 to 4.3.3 and there are obviously significant changes, more so in the ACP than in the user area.

Under 3.4.8, I had customised the way deleted members were displayed, but only using built-in ACP functionality. I didn't buy any external plug-ins or hack any files.

I just cannot seem to find those settings in 4.3.3, and the settings appear to have been reset, prefixing Guest in front of the username instead of bracketing it as I had.