Intermittent brake / main light problem

Hi there

Novice and new land rover users here....so please bare with us!

we've just noticed one of the rear brake light bulbs have gone, so we've replaced it. however, now the brake lights are not working at all, but the lamps will illuminate when the main lights are put on - any ideas why??

thank you!!!

its ok - just changed the fuse and it works - sorry to bother you all!!!!