Replace / Alterate Bay window

[Rad1o]

I want to do the outside sitting room end up. This end has got a wooden bay window with 4 front panes and 2 side panes in. The frame is o.k. and has a decent thickness. I have replaced all the panes before about 12 years ago to ones with a better insulating property.
The wall is solid brick and I want to put drywall insulation on from the inside - the rest of the house has, I have just shied away from this window.
Now I thought my options are
1. Complete new bespoke and ideally triple glazed window or
2. Router the frame down to give me and additional 20mm.

How easy or complex and messy will it be to go round the frame pane by pane???

 

[Gazman16]

Just replace the frames.
Double glazed units dont last long in timber especially without careful consideration of things like edge seal cover, ventilation and drainage.

I wouldn't worry about triple glazed not really worth it unless your in a cold climate or have massive floor to ceiling windows.
If you do still decide to go for triple glazed make sure they are at least 44mm thick, Basically anything smaller is no better than double glazed

 

[StephenStephen]

If the frame is solid and has decent panes in, it would seem silly to remove or replace. My inclination would be to add an additional layer of glass on the inside, which I've done in 2 different ways in the past, successfully:
-router a rebate on the inside, put a narrow tray of water collecting crystals in the bottom, fix in single panes with beading
-use a magnetic and polycarbonate secondary glazing (it's usually cheaper to buy the magnetic tapes from ebay - the polycarbonate kit companies are reasonable for the glazing, and sting you for the tape.)
You could combine the two - rebate out for the polycarb and 2 mm for the tape - that way you can pull out to clean and deal with any condensation.