"Hopefully, the amount we claim for the cost and installation of our garden office will more than offset the fact that we are unable to claim an element of the household running costs. Other allowable costs include:Tomorrow, Moving On...
• Telephone (including line rental) apportioned by call time (incoming and outgoing). A dedicated business line can be claimed in full.
• Broadband (as telephone costs)
• Electricity / gas / water. Ideally, these should be separately metered, but if not, we should calculate the extra usage involved on our domestic supplies, and this will be the allowable element.
• Business insurance
• Repairs to business equipment
• Capital allowances (wear and tear) on business equipment (including computers and peripherals, office furniture and fixtures such as shelving etc).
• Printing, stationery, postage and advertising
• Computer software used for business
• Travelling and subsistence costs (a whole topic in its own right). Subsistence relates to the expenses incurred for ourselves only. Any entertaining of suppliers, business associates and, even, customers is totally disallowable.
Motor expenses of running business vehicles (less any personal element)"
Alan also runs a useful blog which is well worth a browse.