Really easy process to do yourself matey, write a letter to your local HM inland revenue and explain that you wash your own uniform etc.
I claimed for boots ( which I had to buy ) and professional subscriptions as well. In your letter include your
NI number, current tax code and how long you have been employed at your company. They will write back to you and inform you whether your tax code has changed.
Also state that you wish to be paid any deductions owed as well, otherwise they wont back date you if your eligible.
Bollox to that company who will charge 41% - bare faced cheek
Good luck