The problem with new taps is that they are no longer serviceable.
You can get the ceramic washers for some taps, and even then, they are different. When we went to France, I even looked in their DIY places, and found all sorts, but not what I wanted.:doh
I have never seen one of those types before, do you know where it was made, or supplied by?
I think a certain way to fix it is to replace the whole tap, but in 5 years time you will have the same problem again.
Some of these taps cost upwards of £80.
We had a similar problem with a swan neck tap, first I replaced the ceramic part, then a year later the seals went on the arm, so it leaked.
There was that much play in the arm, that it was worn out anyway.
I should have cut my losses and bought a new tap a year ago when the ceramic seals started to leak.
Modern junk, sold at extortionate prices, whose paint finish or chrome finish starts to flake off after 13 months.
Just take a look... Made in *****
I rest my case.