Uncheck that box for Alt Speed Display and you'll be fine. That's meant to comply with UK law (I think) that requires new cars to display speeds in both mph & kph.
When that box is checked you get that lovely kph readout at the bottom of your display.
But what if I want it to still be there but displaying MPH? Probably a VAGCOM job? Seems silly. There are few things I miss about my civic, but a digital speed readout is one of them.
Using VCDS (aka VAGcom), if you change your Instruments coding (module 17) to RoW then your digital speedo will show kph (with me so far?).
THEN... if you enabled the Alt. Speed Display you would see mph at the bottom of the display (the opposite of what the OP complained about).