you are right no reply to the 100 above call but at DECIDE call if the PF does not responed then the PNF will exicute a goround.
Further to the above (BA use "50 above"), if no reply is received to "Decide" on a Cat 3 approach, in BA the co-pilot will land as it is considered safer than a solo go-around.
The calls within BA (from the Non-Handling Pilot) are "Power Set", "80 knots", "V1" (if applicable), "Rotate", "Positive Climb" ... and of course "Stop".
The "Stop" call is perhaps the most contentious. Obviously, it can be called by the Captain for any reason, although above 80 knots it would most likely be for "multiple failures". However, unlike in some companies, it can be called by the co-pilot for any of the following:
i) Any fire
ii) Engine failure (two parameters, one on the panel)
iii) Configuration warning
iv) Blocked runway *
v) Control difficulties *
vi) "Monitor Radar Display" auto-callout **
vii) "Windshear Ahead" auto-callout **
* If handling
** Where fitted