Council tax rebanding help please

[Reetpetitenot]

We've just been notified our council tax band had been bumped up 🙄.
The previous owners extended the property a little and added a room above the garage. The valuation people only review when the property is sold for some strange reason, meaning we bought with the understanding that the property was band E and they've now bumped it up to Band F. The criteria for arguing against the increase are fairly woolly and I wondered if anyone has had experience of appealing a similar decision, and what your arguments were?

When we bought our first house we challenged the council tax as the rest of the street was band b and ours was band c. We were successful but our house had no modifications. Not sure how it will work if the house is extended. I’m surprised the solicitor didn’t pick it up as a potential issue.