This explains all!
https://www.thesapodcast.com/18-business-rates/
Generally, Business Rates will be lower than Council Tax and in most AirBnB businesses are zero! This is because "small business rates relief" is usually allowable if you qualify as an FHL (Furnished Holiday Let). If the relief applies and the "Rateable Value" is less than £15,000, the business is "zero rated". Most AirBnB properties have a Rateable Value far less than this. For example, a flat in central Manchester with accommodation for 6 is only £3000 and so Business Rates will be zero. The same flat in central London will probably exceed the threshold, but even then, there is tapered relief between £18,000 and £15000 from 0-100%. My 3 bed, 6 person cottage in Anglesey is £2125 and it is zero rated. I pay no Council Tax and no Business Rates.
If the business does not qualify for small business relief, then the Rateable Value is multiplied by 49.3p to calculate the amount due per annum. If it does qualify as a small business and the RV is above £15000, the rate is 48p (2018-19).
To get your Rateable Value, you have to apply to the Valuation Office Agency