I think that you'd be mad to overpay in relation to this mortgage.
You're funded at ECB + 0.6%. You can easily get a (net of DIRT) deposit rate in excess of this.
For example, BOI are currently offering a 2 year deposit product paying 3% in the first year and 6% in the second year (i.e. 4.5% over the lifetime of the product). You can withdraw the funds if needs be after one year.
If you lodged your €40,000 into the above product, your "after DIRT" take for the two years would be €2,628 [i.e. €40,000 x 2 x (4.5% x 73%)]
During the same period, you'd pay interest of €1,480 (i.e. €40,000 x 2 x 1.85%) on €40,000 of your mortgage (at a current rate of 1.85%).
The ECB rate would have to rise a hell of a lot before paying down your mortgage would make sense, and even then deposit products "beating" your mortgage rate should be available.