Throttle body heater should not be bypassed as a permanent fix. It is a $21.95 part that could be changed in a half hours time.

 

you might want to also remove the hoses from the idle air control bypass motor thingy and see how gummed up that is.

you can leave the tb bypassed with not worries unless you live in high altitude/latitude. a frozen butterfly on the highway in winter is a worry for some people however. i've not seen proof on discos but ive seen plenty of dyno reports that show a modest decrease in air inlet temps with a bypass which might improve power/effeciency negligibly