DH and I live in an apartment in a big city (not in UK) and in September we got two rescue kittens, who live with us as indoor cats, in common with the vast majority of cats who live in this city. They are wonderful cats and we love them to bits. They are very happy and playful, eat well, are clearly healthy and incredibly affectionate. They love cuddles and will sit on us for hours, greet us with cuddles and purrs when we come in and are generally delightful.
Our issue is with one of the cats, who will not stop meowing at night! She didn't do it until recently but now it is becoming a real problem. Our bedroom leads directly out from our living room and the cats sleep in the living room at night (they have a cat bed, a blanket and a cat tower with several sleeping places to choose from). However, from about 4 am one cat begins meowing loudly outside the bedroom door and doesn't really stop until we get up at 6 for work. She isn't hungry or thirsty because when we get up there is always food and water left in their bowls. I think she just wants attention but we can't give it to her at 4am!
The cats can't sleep in the bedroom with us because they are very playful and disturb us too much by attacking our feet 
Does anyone have any suggestions as to how we can sort this out? We love the cats dearly but being woken at 4am every day is getting tiresome...
Thank you!