Ultimate list of tax deductions

I'm trying to develop an ultimate list of 'extra' tax deductions which you could claim for clients, these would be items which a client may not think would be qualifying themselves.

So far my list is fairly small, but I would appreciate any help from other AWeb members;

Use of home as office (either £4 per week or actual costs if higher)
Capital allowances on own car or van (based on business use)
Laundry costs
Clothing costs (protective) or flat rate if employed

If you have any others you can think of, they would be gratefully received.

Many thanks.