Assuming, As I will, that the (scottish, and Units in other territories I control) British Units are now under my Command. Utiliseing the fact that the Scottish Have access to the only Nuke Deterrant in the Isles of (former) Britian In the form of Trident/Submarines.
Utilising singal warheads in a tactical role to destroy enemy Army build ups to destroy their armies cohesion, Secure Northumberland and The north of England, Further attacks will be met with deadly force and single nukes.
Money must be spent to ensure that industry is built up again, particular attention to high Tech industries already present in Scotland (silicon glen, the large Bio industry etc). Utilisation of spare submarines/naval forces to secure and protect Scottish Oil and Gas Rigs.
An effort must be made to secure the British Isles and reunite its people, once Scottish Dominance is secured offers of a Council will be made to the remenants of the British Isles. Britons must face the uncertain future.