The cost of anything that is necessary and essential for your duties as a director will receive tax relief. This covers computers, printers and software. You may also claim reasonable relief towards the cost of equipping/ furnishing an office, e.g. chairs, bookcase. This may appear to hold a dual purpose, but it is allowed because it is a consequence of a business necessity. As long as the personal use is insignificant it will not be treated as a benefit in kind and you will not have to pay National Insurance or income tax on it.