Confused about business rates for home business

[s1962a]

I've been reading up about the rates payable for a home business where the garage is converted into a clothes designer studio, where clients can visit and purchase clothes. The business rates calculation seems to indicate the value of the whole property is taken into account and then business rates calculated from that. Is that right?

I would have thought they would work out the rates by the value of the proposed yearly garage rent rather than the whole property? Or have i got this all wrong?

Cheers

[s1962a]

also would rates still be payable if part of the garage was used for domestic use - i.e. storing gardening equipment and kids bikes etc?