Trying to remove the tap lever on above mentioned mixer, model no. 33281001 and not having any joy.

I've removed the screw cover and the allen grub screw, but nothing seems to budge. I'm assuming it needs to be pulled straight upwards?

Would appreciate any pointers.

Incidentally, the cartridge has become stiffer over the past few days. We live in a very hard water area. Before I shell out most of the cost of a new tap for a new cartridge, would soaking it in descaler help to loosen it up?