I am not an expert but, If your clothes are not normally worn in everyday life, i.e overalls or lab coat, or very perscriptive you may be able to get the tax back on them, there was a case some years ago with a female barrister and the black suite she had to wear in court and wether it was everday clothes she could wear outside work.
It the clothes could be considered PPE (Personal Protective Equipment) your employer must supply them to you free of charge.
As for laundering them, nurses do get tax relief on this but it may be a special negotiated thing with the tax office, and because the uniforms must be washed seperatly and on a hot wash.