"Why would he want to speak to the Vulcan?"
Heaven knows why he broke OPSEC in that way. He was tasked to provide AD cover to the Vulcan raid, not to compromise it.
"Why did he even know it was inbound?"
All Britisn action was, of course, coordinated. The Vulcan attack was notified to the Task Force for operational reasons, fairly obviously.
"Where's the BS Beags?"
Read his book (don't buy it though) - and you'll find out.