Last July we suddenly got a bill from Octopus for over £8,000 (in addition to the monthly direct debit we were paying and despite never going more than £600 in debit over winter). When I called them I was told that they had been unable to get ratings from my smart meter for over 9 months
I get twitchy when I dont get the bill on time and give it a week before I get in touch with them. Sometimes it has been due to the lack of automatic readings which got sorted after they managed to read the meter but lately (past two months) all the data is there and it's still happening. It takes them long enough to sort 1-3 months readings as they have to do some manual work so I can only imagine what 9 months wroth would be like, hence I keep a tab on it.
Im not risking putting anymore manual readings in since last time I did, I ended up putting my export reading into the import readings and ended up with a 6k bill