The question of whether the numeric space should be listed at all is addressed in Braille Formats Appendix G which lists the symbols that are required on the Special Symbols page (SSP) if they are used within a braille volume. The numeric space is not listed. The second list in Appendix G lists symbols that are new with the approval of UEB. These symbols may be included on the Special Symbols list. Again, the numeric space is not listed.
Braille Formats §2.5.1 states that the Special Symbols Page "should list symbols found in the volume that may be unfamiliar to the reader." The numeric space did not exist in the previous code— English Braille American Edition (EBAE) —so it is safe to assume for some braille readers it could be unfamiliar. So whether to list them on the SSP appears to be an agency or the transcriber's decision, —but isn't required.
If you decide to list the numeric space symbols, note that UEB §6.6 does not show dot 5 standing alone. Dot 5 is a prefix that comes before many UEB symbols from the opening parenthesis to the long dash. The numeric space is a unit comprised of two cells, —dot 5 followed unspaced by a digit. (Since the numeric space occurs in numeric mode, only the first number in the symbols-sequence is preceded by the numeric indicator.)
There are ten numeric space symbols in UEB 6.6 that have the meaning "space and following digit." The exact description is not prescribed, but each two-cell numeric space symbol appearing in the volume should be listed on the SSP separately with a description meaning "space and following digit" for the specific symbol. Suggestion:
.="b Space followed by 2 -or- .="b Space followed by 2 in numeric mode
I hope this provides some direction. If you have further questions, please don't hesitate to ask.