I dont think you apreciate the new found Englishness. The relationship would not be one of animosity or hatred but us English now feel more confident in demanding our own parliament. Even Brown was making a play for the stengths of the union the other day. Scotland is dominated by Labour, who are struggling against the Nationalists. The tories have no seats. If Scottish seats were not counted in the general elections then the Labour party would find it difficult to ever get control of England again. Hence they fear separation, just as to the tories it would make no difference.
The nuclear detterent would not be supported by the Scottish Nationalist party, they would want the boats and facilities to leave scottish territory and probably a bigger control of oil revenues from Scottish waters. The Scottish labour party and the Nats would not support military operations in Iraq and probably not afghanistan.
Therefore there would be very real difficulties in keeping military unity under two parliaments who would want autonomy. A politically independent scotland would not necessary agree to scottish regiments taking part in ops with the US.
As I say , English taxpayers would not accept Rosyth getting contracts for warships paid for by English taxpayers.
Unless you are a Brit, it is hard to understand the relationship between the English and Scots, it can range from subtle banter to out right hatred for the english by some scots, we would never go to war but each wants to run its own affairs, own taxes and own policies.