Help with tap?

[Davalan]

SOLUTION
I tried a strap wrench but it kept slipping off. In the end an old adjustable wrench was able to get some bite on an edge and the chrome cap unscrewed anticlockwise as was thought. See Photo.
Thanks for all the help.

 

[Best]

Glad you finally got the top off. I also found the strap wrench to slip off the rounded top piece, but I kept trying it numerous times until I unscrewed it.
When you refit the top piece, or any of the head parts, use a dab of Vaseline or silicone grease on the threads and spindle end, etc. That way, it will all come apart for some lucky person next time.