davewhiteside, do you drive a car?
Do you know how long a journey will take?
If you have to drive a set distance at a given speed to arrive at a given time do you just set off and ring your girlfirend when the meeting time is passed?
Do you spend lots of time sittting in car parks?
No need just do the maths. Maths is a language. Its easy.
You do not need trigonometry, calculus or rocketry (it helps) but you do need to be able to use a formula, In my day it was algebra.
Simple time and distance sums plus good addition and subtraction, the ability to convert and you are half there.
Remembering (even knowing) all the imperial-metric conversions makes life simpler.