Help fixing dropping tap but cannot remove the head

[jhs2zz]

The water tap has a dripping problem and after done some research like the 'How to fix a dripping tap' video by B&Q on youtube, I think it's the o-ring problem. I tried to follow the videos to open up the tap and look for the o-ring, but I get stuck after locating and removing the nut with an allen-key.

I have filmed the process and share my video here: https://tinyurl.com/y6quao5v. As you can see, I have got the nut out, and I think the next step is to remove the head of the tap and then it should reveal the structure underneath it. However, I have tried very hard brute force (I did try two hands but not shown in the video as my other hand is holding the phone), used a wrench to wedge it open to the extent that it kinda damaged the metal casing. But it still won't give.

[stoneyboy]

Hi jhs2zz
Suggest you squirt wd40 in the screw hole, leave for a day then try levering the head off as your video but use levers on opposite sides of the tap.
Regards S

[jhs2zz]

Thanks, that works!