These facilities were built up over the last century by Scottish interests as well as from other parts of the United Kingdom. When the white paper Scotland’s Future suggests a willingness “to co-locate with the UK in current premises” that suggests to me a civilised division of the spoils.
It would be in the mutual interest of Scotland and the rest of the UK to share these trading assets. That is not taking for granted the goodwill of rUK. It is arguably simply good international economics.
Whether we become competitors or allies depends very much on the details of the post-referendum settlement.
In some ways this issue is similar to the debate over currency. A currency union will operate well if the partners enter into it with a spirit of co-operation.
There is a rational case outlined in the white paper for setting up autonomous facilities in some countries post-independence, and sharing them responsibly in others. Why would we want to do that?
Because it is a mature way to ensure an effective transition for the trading interests of all component parts of these islands after Scottish independence.