Not to fear. I had every confidence in the chap taking that into account
🙂
Anyway, you know what I'm like when some has a setting out query and I have some form of CAD in front of me.
This is what I think basically
@3_fall is getting at. In this picture, the dotted line is dead centre of the window. I started the first course below the window exactly 150mm to the right of that line. Although not 100% accurate in terms of making the correct size pieces of the wrap-around corners, it doesn't look out of place and eliminates eye catching slithers.
Grab a pencil, tape measure and spirit level and draw it on the walls before you begin just to make sure
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