I am in the second year of running a self-catering B&B business from part of our home. The first year the income was miniscule and I didn't bother setting any costs against the income, just declared the lot! The second year is a different matter as we had a really busy spring and summer season during 2011

. Does anyone know how I calculate the percentage of council tax, electricity and heating bills I can claim as a business expense? I do my self-assessment tax returns myself and am not sure what is reasonable to put down as business expenses vs income. Our house only has two bedrooms, and effectively we let out one third of the house..should I be using 33%

Any help gratefully received. Thank you.