1-what formation do you allow units move over or fight on bridges?
Generally, the unit must adopt a formation that allows it to fit across the space that is the bridge. This will require an order to change formation. If you wish to declare that it is an attack column, then you may do so, but make sure that your opponent is aware. Usually a march column will be used to cross a bridge. Fighting across it, I suspect would be an Attack Column.
2-same question re fording rivers?
Depending on the depth of the river or ford and how long it is, a unit can cross in any formation that the restriction will allow. If it is a shallow river or stream, a unit could cross in line.
3-replacing killed officers?
Usually the replacement has 1 less command level.
4- if an officer is still attached to a unit from the previous turn ;say doing a rally or follow me action .Can he next in the next turn issue orders while still attached etc
Yes. He can also move away from that unit in his movement phase.
5-i was caught in the flank twice in our latest battle and survived well due to unusully good dice from me - is the (- 1 too light for that situation?
Not really. Did you remember that you can only use half of the unit's total attacks to the flank? That coupled with the -1 is penalty enough.
6-if you want units not to move have you to order them to hold each turn or if they achieved their orders last time do they require further orders to hold until you may want them to move again in future turns? i appreciate units must keep trying to achieve a previous failed order until they ae issued new ones or finally arrive LOL
A unit only needs an order to move or change formation, so there is no need to order a unit to hold. A unit does not need to keep trying to achieve a previously failed order. If you failed an order in a previous turn and you still want the unit to make the same move, then you attempt to give the order again in the next command phase. If the circumstances change, you can attempt to issue a different order. Once an order has been attempted, successfully or not, that is the end of it. The unit does not have to carry on trying to fulfil it.
7- do you use any form of cavalry in attack column -esp used by the untrained recuits in 1813-14 -Murat @ Liebertolkwitz also frees up some tabel frontage space
No. Attack Column is an infantry formation in BP.
Hope these help