Anathema here I am sure but can't you just extend the logic in one of the above messages about sizing Scotland's armed forces to the English situation.
Small country, marginalised off the coast of Europe, oil and gas and fishing to protect.
Who do we go to war with?
Russia-don't think so
America -also don't think so
China too far away to care about us anyway
EU pretty unlikely with the ruling classes having second homes in France and Spain and driving Mercs and BMWs
Army
A fair number of squaddies for parades and keeping prols and chavs in their place, helping people in floods and keeping an eye on any IRA resurgence
Navy
Some decent patrol boats for looking after oil and fish-unless that's all gone with Scotland
HMS Victory and HMS Belfast to remind us what a navy was
A few helicopters for the royals and to ferry the squaddies about
The Red arrows
BBMF-same role as HMS Victory above
There you are a defence policy for 2020
Or maybe I am being too simplistic