Don't let it get to you Nelson - take a brake, have a brew and come back to it. It is by rising to these challenges that you will become a better model maker. You CAN do it!
Thanks, I will leave it till the morning. I'm glad someone believes in me. The problem was, I had completed the first window, but trying to copy it and make another one is proving a challenge.
To replicate dimensions accurately, use a pair of dividers, compasses or the best is a vernier gauge. That way you are copying exactly. I hope this helps!