"Can you please provide evidence that everyone knows the RN is stretched to breaking point?"
I really don't know what to say except to ask what desert island you've been stuck on for the last 10 years...
Look at this thread - there are dozens of links to various studies and statement by experts, and RN officers.
Read the Times or the Telegraph - letter after letter, article after article........... same with the BBC
Read every edition of the annual "British Warships & Auxiliaries" for the last 15 years - or the annual authoritative "World Naval Reviews" - or "Janes"
In 2012 the Chief of the UK Defence Staff stated in a lecture at Oxford "One of my biggest concerns is the number of frigates and destroyers the Nay has" - at that point it had 24-26 vessels - you now have 19