If I cancel my Way-in transfer, does that cancel my Return transfer too?

No, a round-trip transfer is equal to 2 bookings: the Way in and the Return transfer. So if you cancel the Way-in transfer, be aware that the Return transfer is still valid, and vice versa, so remember to cancel it too if necessary.

Reminder:
Cancel your bookings by going to My bookings and then click on the booking you wish to cancel. You will then find a "Cancel my booking" option.