Not sure it was a particularly cunning plan.
I’m quite sure the Russian’s were fully aware Britain kept or keeps most of its Nuclear Arsenal in the West of
Scotland.
The US Subs have left The Holy Loch but The British ones are still at Faslane.
She was used back in the 80’s to pick up British and other foreigners from a war zone in Yemen when things got dicey.
A cousin was an artificer at the time.
In reality the hospital ship was probably just a ruse to justify the
budget.
Although I suppose she did provide a secure location for Royal visits abroad.
Travel to exotic places was probably seen as a perk by crew.