Help with France (Where are the British?)

As a warning I'm a newish player to HOI4 (only 80 hours). I've been trying to do a Democratic France run and have followed the advice I've seen online (building forts on the Belgium and Italian borders). I've been holding on but just now the Germans broke through (after a year of attacking) and I'm wondering why I haven't seen any British or Commonwealth forces come and help me defend? All I've seen them do so far is launch ridiculous unsupported naval invasions into Yugoslavia and it's quite frustrating to not receive any help in France. When I've played as Germany I find that British forces always deploy in Europe against me so I'm confused why they don't help me now.