Advice needed on tricky external corner with trim

[Jack07]

Hi,
I'm tiling my bathroom and have encountered a tricky corner. On one wall I have floor to ceiling tiles (shower) and on the other I am only tiling half way up.

The problem I've found is where I've left a small lip on the half tiled wall with the trim now sticks out from the tiles up. It's only plasterboard at the moment and I am having it plastered but I have a thicker mosaic border at the top which will be pushed out further than the trim!

Has anyone experienced a similar problem?
I will send a pic when I can.

Thanks jack

 

[jctilingservices]

finding it hard to visualise what you mean mate, a pic would be a lot more helpful if you can upload one