Hmmm, I did a Google and discovered that a MGA coupe is not an aeroplane.
Let alone a Type Certified one registered in Australasia.
There will be any number of guys on these forums with mechanical aptitude and skills. I work alongside such owners regularly and they are resourceful and great company.
Invariably their knowledge of the regs is near non-existent and they are keen to listen and learn. That said, every airfield also seems to have a 'character' that knows more than everyone, and anyone, else.
The cleaning of the windscreen was easily sorted. The OP got some good replies.
The option of replacing the windows is still there and available.
Listening to someone that says you can make some replacements out of cheap acrylic sheet may not be such a good idea.
Indeed if you want to remain legal it is not an option.
I thought the best advice was to have a word with the LAME if you wanted something installed.
I very much doubt it would take 3 pages to get the correct gen. A few minutes would do it and how much would you be paying for some sound advice ?
I remember asking a question on a Cherokee forum once. How many members had actually endorsed an aircraft logbook with a Release to Service or similar entry. Not one person replied.
Perhaps we could ask here...
How many guys here have actually certified the fitting of replacement windows to a certificated aircraft ?
*** EDIT ***
https://www.youtube.com/watch?v=E-vz-BnPOPk