Valid points! We thought about these things, but we had limited time and we couldn't get to them. As for the route suggestion - this isn't up to us. It depends on our data source and what results it returns.
Thanks @GrumpyNI, I'm currently in Amsterdam, you guys sure as hell have a lot of Teslas :) Happy we've hit the mark, although our calculations are based on estimations, we've done our best to keep it as relevant as possible.
It's awkward having the MPG and overall CO2 emissions on separate folds of the screen. I shouldn't need to scroll around to access ~10 numbers.
Also the UK is weird, we use MPG for fuel economy but will measure CO2 emission in kg.
Your transit calculator misses the opportunity to suggest a combined bike+rail trip which is the most practical.