I thought we had a clarification on this?
Not quite. There is no mention of a wheeled scrum, but I have highlighted the part which I believe is relevant to the OP's situation.
[LAWS]
Ruling in Law by the Designated Members of the Rugby Committee
Ruling
3-2009
Union
FFR
Law Reference
5
Date
8 April '09
Request
Law 5.4 stipulates that
“time-keeping may be delegated to an official responsible for time keeping”.
Law 5.7 (e) stipulates that
“if time expires and the ball is not dead or a scrum or lineout has been awarded, the referee allows play to continue until the next time that the ball becomes dead.”
The ball is dead
“when it has gone outside the playing area, or when the referee has blown the whistle for a stoppage, or when a conversion kick has been taken.”
Law 20.4 (g) sets out that
“if a scrum collapses or lifts up in the air without penalty a further scrum will be ordered and the team who originally threw in the ball will throw the ball in again.”
Following these provisions, the FFR would like a ruling from the Designated Members with regards to the situation as described below:
1. The referee awards a scrum for Team A.
2. After blowing the whistle for this scrum and setting it up, there is the siren indicating the end of the match (real playing time).
3. The referee allows for this scrum to be played.
4. The ball is put in then the scrum collapses without any penalty from either team.
5. The referee blows the whistle.
The “technical” decision to be made would be to award a new scrum.
Question:
Does the referee have to have this scrum played or does he have to blow for the end of the match?
Ruling of the Designated Members of the Rugby Committee
Despite the Referee being able to delegate responsibility for time keeping the referee is still the sole judge of fact and Law and the game ends with the referee’s whistle.
The scrum has been set in playing time and collapses. The referee is obliged to blow the whistle in accordance with Law 6.A.8 (g).
The original scrum has not been completed and has had to be reformed in accordance with Law 20.4 (g) and therefore the match would continue and end at the next stoppage of play in accordance with Law 5.7(e).[/LAWS]
NOTE: This is not the whole clarification. The rest of it concerns a line-out on full time, so I have edited the references to that out.