Mrs Stewie and myself have visited the Isle of Wight on several occasions over the last couple of years and one of the places that we visited is the Needles Old Battery, built to protect the western end of the Solent from foreign naval incursions. Many of the accommodation features of the Battery are common to the 'outer ring' forts surrounding the Medway towns and it even had a 'rolling' entrance drawbridge similar to that installed at Fort Luton I believe.
The interior of the Battery's case mates have been restored to something approaching their original condition and been whitewashed to brighten up the interiors.
Although not Kent related, I have taken the liberty of including a few photos in the hope that some of the historians of this period may find these useful.
Photos 1 to 4 are connected with the case mates and the lighting / ventilation passage, whilst photos 5 to 7 are associated with the lifting bridge and its winding mechanism. Interestingly, if you look at the drawbridge winding mechanism, you can just make out two 'windows' in the vicinity of the winch operator. At the entrance to Fort Luton, there are two 'filled in' square holes which may have been equivalent windows.
Should anyone have any questions about these pictures let me know and I may be able to help. The Battery itself is an English Heritage site and has its own website as well.