The expression doesn’t fail, it just doesn’t round(2), I have successfully used this function in other templates this is the only one where I am multiplying the result of 2 separate sensors states and need to round the entire. Maybe I need to encompass in brackets
yep that was it thanks for the sounding board
"{{ (states('sensor.aud_to_usd')|float * states('sensor.usd_to_gbp')|float)|round(2) }}"