EFT Worries
Why are you using a 40nm radius wind velocity from the aerodrome forecast rather than interpolating from the Met Office's 6-hourly F214 low level spot wind chart?
If you have current aerodrome 40nm radius forecasts for each leg of the route, then perhaps.
Otherwise one should use the charts for their intended purpose, I would suggest.
Otherwise one should use the charts for their intended purpose, I would suggest.