I may not know much about plants but I do remember my favourite book (?) about them!
I recommend Richard Mabey's article in Flora Britannia. '65% are found in woodland, with 16% being recorded from hedgerows. Other habitats supporting bluebell are scrub (6%), grassland (8%) and tall herbs (2%)' in Birmingham and the Black Country. 'Not surprisingly, the native bluebell was most often recorded (71% of records) in broadleaved wood/scrub habitat.' and 'It thrives in shady habitats such as broadleaved woodland where it can dominate the ground flora' say Plantlife. Perhaps as farming became more efficient the woods beacame the normal place to see bluebells.
Turner mentions it in 1548 as being 'aboot Syon and Shene' - not many woods around there even then, surely? - although no doubt it might be preserved in Harrow Park - not my area, really.
Gerard (1597) knew it 'wilde in woods, Copses and the borders of fields.' In 1660 Ray recorded it in 'Madingly and Kingston woods', as you might expect. That's very different from referring a wood as a 'bluebell wood, of course. Maybe that came in with railway tourism?