I’m sure the survey will evolve with the version most suited to the needs of the time surviving, much like life has, unlike life the other versions will probably still be around if they are needed.
I once surveyed someone else's dig/small discovery and was was not thanked for my efforts. Once bitten, twice shy. And anyway, I don't get down to Somerset often enough for my liking. Sounds like a quick evening job for a local.
Well worth a trip since the recent extensions (within the last year or so - not the original push of 4 ~ 5 years ago!!)
And as to kit - it depends on how good you are at climbing - good climbers need no ladders (pitch head is the crux so big drop if get it wrong) ok climbers will only need one ladder as the bottom pitch can be free climbed directly (tricky) or by stepping around to the right, facing out from ladder which is a fairly easy climb. Obviously those with no climbing ability or head for hights will need the aforementioned 2 ladders.
And if it's not enough of a trip - there is always drunkards and rods within spitting distance.