This might have already been answered deep inside another topic, but I can’t find a straight answer, apologies.
Scenario - I create a bills pot that I xfer £1000 into on payday. My bills are usually £1000, but this month one bill is higher, so the bills total £1050. Will Monzo automatcially take the extra £50 from my main balance to cover the shortfall?
Thanks in advnace.
Yes
muchas gracias, mi amigo 
Where did you see this? From what I read, it says that if your pot is short then it will not automatically take money from your main account.
Right now you have to manually top up your Pot to make sure you’ve got enough to cover your bills. If you don’t have enough in the Pot to cover a bill, we’ll take what we can from the Pot and then make up the difference from your main account.
https://monzo.com/blog/2019/09/26/introducing-salary-sorter-and-bills-pots
Where did you read that? It’s very much the opposite. When a bill pot transfer goes out, all that happens is the money is moved from the pot to your main account seconds before the bill is paid. This means anything over the amount you had to be transfered will just come out of the main account aswell.