Thank you very much for the contributions above; they're a great deal of help.
In the O.P. I deliberately didn't explain why I was asking the question because I didn't want to influence any answers. A query has arisen about the cave's name, which I'm trying to sort out for the new Northern Caves database.
The existing Northern Caves guide and the Ordnance Survey have Yew Cogar "Cave" but The 1959 edition of P.U. uses Yew Cogar "Hole", as does the article describing the main extensions (CPC Journal 1971) together with the definitive survey of the whole cave (with CPC Journal 1972). I just looked at Psychocrawler's suggested reference (CPC 1966) and note that it also refers to Yew Cogar "Hole".
Langcliffe's narrowing down of the first caving guide reference is also very helpful; Langcliffe, if you have a copy of Britain Underground 1953 to hand, please could you glance at the entry and see how it's specifically named? Thanks.