2012 Law Changes http://www.irblaws.com/2012/
(Implemented from the start of the Northern Hemisphere Season or 1st January for Southern Hemisphere.)
Changes:
Law 9: Method of Scoring
Conversions to be completed within 90 seconds of award of try
Law 12: Knock on or Throw forward
When the balls goes into touch from a knock on or throw forward, the non-offending team has the choice of a lineout where the ball crossed the touch line or a scrum at the place of the knock on / throw forward. The non-offending team may exercise the former option by taking a quick throw in.
Law 16: Ruck
When the ball has been clearly won by a team at a ruck and the ball is available to be played the referee will call “Use it” after which the ball must be played within five seconds. If the ball is not played within fie seconds the referee will award a scrum and the team not in possession of the ball at the ruck is awarded the throw in.
Commentary: Five seconds only starts once the referee has called “use it”. Rarely happens in a game as most scrum halves play the ball when it becomes available. If an effective counter ruck occurs after the call, tough, the scrum half should have played the ball when he had chance or got better protection from the forwards!
Law 19: Touch and Lineout
For a quick throw in, the player may be anywhere outside the field of play between the line of touch and the player’s goal line.
Commentary: Unlikely to occur as most lineout will have formed before the ball has been retrieved and taken back to the line of touch without being touched by a spectator or another player.
Law 20: Scrum
The referee will call “crouch” then “touch”. The props then withdraw their arms. The referee will then call “set” when the front rows are ready. The front rows may then engage.
Law 21: Penalty & Free Kicks
A team awarded a penalty or free kick at a lineout may choose a further lineout, they throw-in. This is in addition to the scrum option.
Commentary: Only likely to come into effect at a lineout 5m from the opposition try line. This change avoids the time taken to kick the ball back into touch to take the lineout again from the same location.

Effectively no change:
Law 3: Number of players
Only affects international matches and sevens (up to five replacements now permitted)
Law 4: Players' Clothing
GPS monitors permitted, female players allowed to wear tights, new specific sole configuration permitted as trial
Law 6: Match officials
Extension of the jurisdiction of the Television Match Official

Replacements / Substitutions / Interchanges, RFU Changes
http://www.rfu.com/TheGame/~/media/Files/TheGame/Regulations/RFU%20Regulation%2013%20(1213).ashx
League matches at Level 5 and below:
Regulation 13.5.6
Number of replacements and substitutes in all League Matches shall be: below Level 4 not more than three (unless a variation has been authorised by the Organising Committee.
Regulation 13.5.14
In a match where consent has been given by the appropriate Divisional Organising Committee, each team shall be permitted to use rolling substitution of not more than the maximum of 8 (for three replacements).
Regulation 13.5.16
After the permitted player interchanges have been made no other replacements, substitutions or player interchanges will be permitted for any reason including injuries and in the event that a player is injured the team will play with one less player and with uncontested scrums in the event that this involves a front row player and the game cannot continue safely with contested scrums
Regulation 13.5.17
Player interchanges replace the "blood bin". If a player has an open wound and thus has to leave the field, and the team has used all of its permitted player interchanges, that player may not be replaced and the team shall continue with a maximum of fourteen players. The player is permitted to return once the wound has been treated and the bleeding stopped.
Regulation 13.5.18
Not more than two player interchanges per team may occur at any one time and may only occur during a stoppage in play and with the knowledge of the Referee who is entitled in his sole opinion to refuse to allow or postpone a player interchange if he believes either that the interchange would prevent the opposition from restarting the game quickly or it would not be safe for the replacement player who has been previously injured to play in the match.
Regulation 13.5.19
A player who is a replacement shall not be entitled to take a kick at goal until a passage of play has taken place since that player took to the field of play.

Surrey Reserve League Rules 2012-2013: http://www.surreyrugby.com/pages/pv.asp?p=surrey395&fsize=0
• Replacement of injured players and substitutes will be permitted up to a maximum of 7 players.
• There is no specific requirement for clubs to have specialised front-row replacements in the event of injury.
• A previously substituted player may return to the field in the case of any injury (of any sort) to another player as per the IRB law relating to blood injuries.
• Rolling substitutions are not allowed except with the agreement of both Captains and the referee PRIOR to the kick off.
• There is no restriction as such on the number of permitted replacement ‘interchanges’ (as a substituted player may return to replace an injured player).

Junior Matches
No change - Rolling replacements permitted.

Martin Wilson
Refereeing Co-Ordinator, WRFC