There are certain web sites you will be able to find what you can and cannot charge, so its not quite a private matter as hes not asking for amounts.
So for instance ive sorted a works uniform but according to inland revenue you cannot claim for work clothes unless a specific uniform is a given ie, police uniform is the example they give and the reason; you have to wear clothes anyway. However if you have your logo, you can put them thru as advertising.
Its worth calculating the mileage qay of claiming back compared to actual cost and see which will get u most, ie business insurance, mot, fuel and repairs etc.
Electricity costs of any work associated cleaning ag home etc.
I think we need to organise a window convention abroad so we can claim costs bk on a holiday