I like the fenders Andy, you have become almost obsessive with these but they look the business
Re windows, Rule one, do not use superglue to stick them in place because it fogs the 'glass' and its removal innevitably causes scratches, or the bloomin 'glass' to come adrift leaving you with a square one situation. Uhu like glues likewise risk stringiness on the 'glass' and some corrosion if the 'glass' is styrene based (unlikey but worth thinking about).
Aviation modellers have various canopy glues available from the likes of Revel or Airfix/Humbrol (I think) that do not fog or string and so are more useful.
'Glass' can be bought in sheets as acetate or similar from good model shops. You can use a variety of re-purposed materials including 1.CD cases, 2. blister packaging, 3. Christmas card/ gift presentation box lids, 4. Perspex offcuts, 5. Acetate sheet from stationers, 6. Pouring your own windows using acrylic resin onto a glass base having made your own walls.
The first and forth suggestions are thicker and need to be cut with care so as not to melt or splinter but would be less wibbly. The rest are to varying degrees less liable to corrosion from glues but are more flexible, and so unless cut accurately or fitted into frames* might bow and look squiffy.
Fitting them can be done as individual pieces cut exactly to shape and bonded in with suitable adhesive, they can be fitted inside the superstructure and glued to the inner face of the wall, they can be laminated between an inner and outer wall skins, they can be fitted behind a frame* set into each apeture once paintng has been done and then an inner frame pre painted can be glued in place.
I have read lots and used one or two techniques in non model boat projects before including the poured resin technique in which I created Tudor style diamond pane windows by puring resin over rabbit hutch mech set diagonally 'back in't day' at college.
As ever, I doff my cap to my fellow members who will doubtless have many more ideas and tips all of which makes this place a Gold mine for Model making.