I have two main examples which bug me. The UK CAA instruction for Climb/Descent to a FL, and same for Climb/Descent to an Altitude.
For example - in the UK - "Cleared Climb Fl150".
In ICAO "Cleared to FL150".
Risk of confusing the word To with the number Two.
Then - in the UK- "Cleared Descend Altitide 4,000ft"
In ICAO - " Cleared Descent to 4,000ft"
Same risk of confusion.
Also, the UK document refers to Hectopascals, while ICAO still sticks to Mb.