OK - some decoding:
1986 - The year after Ex BRAVE DEFENDER (Sep 1985 - outline details
here)
URNU - University Reserve Naval Unit
RNXS - Royal Naval Auxiliary Service. A uniformed, unarmed, civilian volunteer service, administered and trained by the Royal Navy to operate in the ports and anchorages of the UK in an Emergency (disbanded 31/3/94)
DEFPA - I'm guessing Defence of Ports and Anchorages, as in RNX role, above.
HMS Nelson - In 1986 HMS Nelson was the name applied to an RN barracks in Queen's Street, Portsmouth, with a support services site within its boundary fence. I stand to be corrected, but I think it was primarily a training unit of some description, but I'm likely mistaken.
All of which would reinforce the point about Home Defence being a role assigned to personnel whose line serials in their Service ORBATs, or who were civilians, meant that they were not destined to be flung into the front line against the Warsaw Pact juggernaut in the event of war, but instead would be Left Out Of Battle (LOOB) on the UK mainland.
Well done sir. All pretty accurate. The point about Nelson in my little tale was that the boarding parties were comprised of the halt, the sick and the lame who tended to end up at Nelson for want of anywhere else to put them. In 1986, the five then University Royal (not Reserve) Naval Units had only had the Tracker class patrol boats two or three years at best, but the RN had realised that nippy little fast patrol boats could actually have some utility in the DEFPA role.
Now, URNU midshipmen like myself had no war role, being technically List Four RNR, but each of the URNUs had a Regular establishment of one Lt Cdr, one CPO Seaman branch, one CPO ME, a Killick ME, and an AB Yeoman, enough to run/maintain the patrol boat per se. The RNR had the Naval Control of Shipping branch, whose job it was to track, organise, assess and allocate all merchant shipping movements in wartime - the old convoy organisation of WW2 in essence - and NCS lieutenants were trained to be boarding officers who could be sent to merchant vessels to talk to the captain, find out about his ship, feed back to control ashore, and instruct him on where to go next - is he allowed into port, or does he need to go to a protected anchorage and wait for a slot to become available, or be completely rerouted, etc, etc.
The problem was that NCS was an RNR officer only sport. In those balmy days of the 80s, the RN blithely assumed it would just round up the halt, the sick and the lame from places such as Nelson, hand them a small arm, and instantly acquire a crack boarding party to back up said RNR officers. Hmmm. When in 1986 we picked up the six matelots who were to be our ship's boarding team, armed with two SLRs and four SMGs, we encountered a slight problem. None of them even knew how to conduct a safety check on their weapons.
Thankfully, no blanks had been issued, but the boss of course did not want them on his ship without the weapons being checked first. Not that he was exactly au fait with the process either, being a Royal Yacht and submarine officer... I am afraid he regarded anything - even THAT rifle - with a calibre of less than 21 inches as unseemly. The CPO Seaman branch looked at the weapons with horror, not having handled small arms since his days as a boy at Ganges. The Chief of the Boat and Killick hid in the engine room. No one even bothered to ask the yeoman. It was left to myself and another midshipman, who had both been in the CCF at school, to take all the weapons off the regular navy chaps, check them, then hand them back once they were aboard. As I originally recounted, we were down one Sterling by the end of the first day of the exercise, after it was dropped by the crack boarding team into Dover harbour.
My CO's views (expressed in his written report post ex) were pretty blunt - if, God forbid, he ever had to do this for real, he would have been far happier if a way could be found to mobilise two or three of us mids, an official lack of war role notwithstanding. As he pointed out, both he and the boarding officer would have preferred someone like myself or my fellow ex CCF oppo, who had by far the most recent range time with such things and if nothing else were far less likely to have an ND, to be issued the two SLRs for the stand-off cover role, remaining on the patrol boat's flying bridge, and let the gash hands run around the boarded vessel with the SMGs. (I did gently point out to him that loaded SMGs carried by the utterly clueless, in confined spaces below decks on a boarded vessel, were a recipe for disaster in themselves...) Of course, a much better solution would have been to have assigned a couple of RMR lads to each vessel, but they were already booked for other ways to die in WW3.
Desperate remedies for what would have been truly desperate times.