I used a slot-cover or datapack case for this. Using a sharp knife I cut off part of the flat side the datapack case and glued it in place in the hole of the comms link case.
Good idea, will also be a good colour match.
My next project is to 'make' (actually re-make) my 128k workshop datapak. I'm struggling to use 'MAKE.exe' with DOSbox via the USB link, so I'm going to have a look at Filip's Load utility and mix in some .ODB, .OB7 and .NTS files. Should be fun. I'll practice on some 32k Datapaks that Peter TheSourcerer sent me with my Top Slot Adaptor cover.