Strange to tell - well, it seems strange to me - I have no recollection of that visit to the hidden valley. I do very well recall that we climbed a hill on the opposite side of Derwentwater, Catbells.
(Not a good picture but one I scanned from an old 35mm slide.)
Actually, this is possibly the most popular walk in the Lake District and Catbells is not exactly a mountain, being only 1,480 feet high.
According to the Wiki, "The fell's unusual name may well have come from a distortion of 'Cat Bields' meaning shelter of the wild cat, although this is not certain. The fell's name is sometimes written as Cat Bells and is so printed on some maps."
Some time after that visit I came across the four books by Hugh Walpole, The Herries Chronicle. Watendlath featured in the books and it was as a result of this that on our next visit to the Lakes we stayed at Watendlath Farm where the farmer's wife, Mrs Tyson, provided bed, breakfast and evening meal.
We would be out all day, but always had to allow at least half an hour to drive along the narrow approach road. This is only about three miles but is a narrow road with passing places - and it seemed that we were for ever having to back to allow another car past. The road runs over Ashness Bridge, from where one of the best known views in the Lake District is so often photographed.
Going on, one arrives at Surprise View, from where one looks roughly north across Derwentwater and south west into Borrowdale.