Thanks to all for suggestions and offers of help - what a great forum this is.
I did persist with bastardising the etched mesh and managed to get this far:
Considering a few days ago I thought this was a window option too far for me, I think it's come out OK.
I'm going to leave it to harden up before adding the remaining woodwork and replacing the roof. The original roof came off with the usual tool abuse as I decided it would be easier to install the windows to the balcony base and build up.
It's been a battle and I certainly wouldn't want to do many like that by the method I've used. Etching would definitely be the preferred option there.
I'm talking to Mickoo off-thread about the possibility of etching other metal framed windows in a certain large building I started in 2013. Thanks to Mick for his offer.