I think a close reading of the rules shows that Chris is off on a couple of points, namely the following:
kenjohns wrote:
(a) The player of the TRUMP Control card may NOT pick “No Trumps” but if it is not in play can the usual Trump Picker, i.e. most Control Cards or tie-break, pick “No Trumps”?
The rules for the Trump Control card state: "When this card is being used in the round, trump is not determined in the normal fashion. Instead, there is no trump declared at the beginning of the playing of the cards. Immediately after the trick in which this card is played, the player who played it picks one of the four suits to be trump."
So if the Trump Control is in the round, the round is automatically "no trump" until the Trump Control card is played.
kenjohns wrote:
(b) If you only have a control card(s) in you hand, that can legally be played, then I assume that it(one) must be played?
Chris has it right here. The rules state: "Also remember that any control card can be played at any time that you would normally play a card." So you can't pass and hold onto the control card. However, you cannot end up with just the Value Control card because...
kenjohns wrote:
(c) If you have the VALUE Control card and only one number card – MUST you play it with that number card otherwise there would be no way of getting rid of it?
The rules for the Value Control card state: "This card cannot be played by itself and cannot win tricks alone." If you have only one number card and this, you must play both cards.
kenjohns wrote:
(d) If the STAR and/or SCORE Control cards are in your hand when the round ends and they are made into tricks – do you score them as being played? i.e. 4 Stars and 20 pts.?
Again, Chris has it right for these two cards.
kenjohns wrote:
(e) How does the ORDER Control card work? The rules and the printing on the card seem to be at odds.
Do you play the card in front of you and then sit out as many tricks as you like. What do you do when you decide to start playing to tricks again? Do you have to play this card to a trick first?
I'm unclear why you think the rules and the card are at odds. From the rules: "When a player possesses this card, it is put out in front of that player and is not played as a normal card.... Once the owner plays to a trick, this card is placed into their partnership's score pile, but it is not treated as a separate trick." And the card reads: "Lay this card out in front of you until you decide to play to a TRICK."
So when you win the ORDER Control card, you place the card on the table in front of you. Whenever it's your turn to play, you either (a)pass or (b)discard the ORDER Control card to your score pile and play a card from your hand.
Using Chris' method, you can't win the trick in which you discard the ORDER Control card. This doesn't match the rules and would make the card less useful. Using the proper rules, you place the ORDER card in your score pile (so you always score the 5 points for it) and play a card from your hand to the current trick, allowing you to swoop in and win a trick that mmight otherwise be lost.