The principal factor which determines how long a joint of meat can be frozen is the amount of fat. Fat deteriorates quicker in the freezer (and at room temperature) compared to the actual meat.
So trim off any excess fat before packaging up the meat for the freezer. Do not remove all the fat though because it adds taste to the meat.
If the joint needs cutting into meal sized portions and / or needs to rolled and tied then ask your butcher to do this for you. The knots required to successfully roll and tie a joint are not difficult but the expert will do it quicker and better!
The picture below (click to enlarge) is of our local butcher (Lewis of Kineton) cutting a sirloin roasting joint for us.
Take a piece of kitchen foil and tear off enough to cover the meat two or three times. Wrap the foil closely around the meat excluding any air. Fold in both edges of the foil, again excluding as much air as possible
Sirloin steak in kitchen foil for freezer
Label up a plastic bag with the date and a description of the contents. Place the foil wrapped meat in the bag and fold the bag closely.Seal the top of the bag with one of ties that came with it and your parcel of meat is now ready for the freezer.