Route description times need to be conservative - 3 hours is not a 'normal' time for someone who is reading a description of the route. I've taken 7 hours to do the through trip, but we were wearing wetsuits, jumping in every pot and generally having a great time. I'd suggest the trip should take 4-6 hours for a group who don't know the cave (it's OK for people to be faster; if you go telling everyone it's a 3 hours trip there will definitely be callouts when it takes them, not unreasonably, 6 hours). Also beginning your description by insulting large parts of the caving community will undermine faith in your route descriptions
I think describing the Wedding Cake as a stalagmite (which it is, albeit a big fat low one) rather than flowstone is probably more useful.
Gnome Passage to Corkscrew: "From the beginning of Gnome Passage, [...] until a large passage heads off to the left" - could make that "heads off to the left at right angles" to avoid confusion with the little oxbow? (maybe that's more confusing)
and "Follow on, keeping right, until you reach a large junction with a steep rocky slope on the left". Probably better to add that it is a steep rocky slope _down_.
Salubrious to Maypole: might be better to describe the 'large drop' as arriving at the head of a 3m waterfall or similar (the Salubrious traverse)
"After a couple of meters, go left at the next junction." - it should be 'metres' but also I think it's probably closer to 10m than 2m?
[Crossroads] "and follow this until it emerges in a small chamber with flowstone on the far wall. From this chamber go right and follow the obvious way down more rifty passage to step over a passage which steps over a passage which intersects underneath." I'm not sure this is quite right about the right turn? Survey suggests you just need a slight right-left wiggle; I'd suggest just saying something like:
"Follow this passage until forced to make a bold step across a rift (Maypole Inlet) into a smaller crawling passage".
For the 35 foot climb, you could probably just say 'Descend to the stream level by clambering down on the well-polished boulders' to avoid over-complicating it (your description doesn't really match my mental model of the climb, although it's probably not inaccurate).
Great Oxbow: Probably worth mentioning that if people miss the climb out, the stream will sump within 30m or so anyway, so it's not a disaster to miss it (otherwise people will spend the whole streamway desperately looking for the climb out instead of enjoying it!).
Cwm Dwr: might be worth mentioning to ignore descending routes to the left (out of Flood Bypass) before the climb up to the Piccadilly junction.
Diver's Pitch: the route from the top of the Diver's Pitch (bypass) to the Letterbox is one of the more complicated bits. I'd describe it something like this:
"The draught can often guide you through the next section. From the top of the climb, enter the low crawl to the right. In places the calcite floor has been eroded away making this crawl unpleasant and difficult with bags. After around 15m, make an awkward manoeuvre to the right through a window into a parallel, but fortunately slightly larger, crawl. Follow this crawl in the same direction (downhill), and keep turning right until the crawl begins to go uphill. After crawling uphill for around 10m, ignore a small passage on the right (which leads to the original Diver's Pitch) and instead take the left passage. This enters a rift which is followed steeply up to the left. A low bedding crawl on the right is the Letterbox (from the 'inside'). Crawl into this; opinions vary on whether it is best to enter headfirst or feet-first, face-up or face-down, but the Letterbox should be exited with great care (and with the assistance of an in-situ chain which can also be used for belaying if required) as it emerges over a significant drop in a chamber. On exiting the Letterbox, it is necessary to step over to a small ledge to its right (looking at it from the outside i.e. to the left if looking out) and then descend to the bottom of the chamber."
In the next bit where you say 'smooth window high up on the left' it's probably worth mentioning '(not the descending crawl ahead)' or just add 'easily-missed' to the description (I've certainly gone round that bit in circles a few times before).
The way on at Pwll Twll can also be described as a pair of passages on a shelf that quickly join?
OFD1 (after the Toast Rack): I'd say 'follow the large passage down *and around to the right*' rather than 'follow the large passage down and then take a right following the large route'.
I think something missing from your description is some sense of timings or distance for the longer bits of the route. For example, your description of the stream from entering it at Maypole Inlet to reaching the Great Oxbow doesn't really convey how far it is - in fact it's probably comparable to all the distance done so far in that trip.
It's probably also good to keep mentioning landmarks so that someone reading the description can tie it into the survey (if they were stood in the SWCC LCR, for example).
