You can claim some refund against your travel to work, your clothing, a room in your home as an office, all the equipment needed there such as fax, printer, computer, laptop, PDA etc. You can claim for things such as sunglasses, gloves, winter hat, all sorts of things. If you have a home in UK you will be allowed an allowance to maintain and visit that. However, you will still pay around 25% of your income in tax.
Because EZY informed to late, all pilots lost probably the ability to claim the above for at least 7 month, as probably most did not keep any bills to prove it to the Finanzamt.
For DTM/SXF tax infos, there are enough german pilots with experience of tax advisors, better than looking into the phonebook.
Experience in aviation tax issues, is what counts.