I can explain a bit more of the Axe hole/ Plunge hole situation as it was myself and Kev Hoy who dug the connection back in the 90's. We did quite a bit of exploring on Stanley moor over a few years then and my only regret is that we left things unfinished.
Firstly, the survey is very basic and not complete or accurate. I always assumed it was made as an aid to group caving from White Hall rather than as a detailed survey. The description in COPD is also innaccurate.( I should apologize to John Beck here as I intended to update both for the recent version of COPD but never got it done, -sorry). There is a full stop between"sandy crawl for 60 ft" and "Tight connection with Plunge hole". The "sandy" (muddy!) crawl goes in completely the wrong direction for a link to Plunge hole. It just reads as if that's where the link is.
Kev and I never found any existing link. The closest we thought was a very tight rift which most people miss which is from halfway down the entrance pitch in Plunge hole, back under the entrance and past the stream. this leads to a small chamber in a bouldery area which might be part of the same bouldery breakdown as the main chamber in Axe hole, but we couldn't see any way through or even make a voice connection.
The connection is definitely not for beginners, and is not going to be easy for anyone these days. From the chamber in Plunge hole you drop down the twin holes where the stream goes and follow it down a body size passage. We managed this by diverting the stream down the entrance rift rather than the twin holes but the stream has altered and comes in via a small sump and it would be very hard to divert it away now. I wouldn't really want to crawl down that passage with a stream backing up behind me!
After just 30ft you get (if you can get into it, we had to dig out the bed of the stream and it was very tight when dry) to the bottom of a small shaft, Feet first chamber. the stream sumps and when we got into it the shaft was capped. We did a survey loop and found that we were under the edge of the large chamber in Axe hole and a relatively short dig uncovered the shaft. The top of the shaft was capped with a big round rock as if it had been deliberately placed to hide the shaft. You can't miss it if you are in Axe hole main chamber with the noise of the stream. If you want to try and do the connection then you must have a look from Axe hole side and see if you think you could get through first. It may be a tiny insignificant cave but there is a serious risk of getting stuck in that link.
In spite of the derogatory opinions expressed by some about these caves, they are interesting and enjoyable in their own way. A couple of hours would be enough to see all of Axe, Plunge and Perseverance pot. Sadly, I believe Stanley Moor cave was "landscaped" a few years back and is no longer accessible. If I am wrong about that please let me know.
Tim