Leaking nappy at night

Elysia • Baby girl born Feb 2019!! 👶💖 followed by 3 angel babies 👼

So little girl is nearly 6 months old and sleeps mostly on her front and all throughout the night- 9/10 hours

Recently she has been leaking out the front of her nappy where she is on her front but the back stays dry- she doesnt leak in the day but then shes changed more often- her nappies arent too small for her and the next size up is too big and I have to crossover the tabs, shes in size 2 currently....

Any suggestions?