You know that is actually difficult to answer, If all the other pieces of the equation are strong then the security may not be requested at all so it is not an easy one to answer.
I would say subject to good credit status, the loan making sense and supporting documents to assist the lender make a yes decision that security may be requested at maybe €10k..?, that is subjective and depends on credit history, the Bank you have been dealing with for years may use a credit scoring model that could suit you, only you know your history and no security may be required, go make an appointment and get yourself credit approved even in principle.