Dripping Tap

[Fluke]

I've got a dripping tap on the cold water side. It's about 4 years old and I bought it in Howdens, it is very similar to the one in this picture, the levers are identical.

https://www.howdens.com/kitchens/kitche ... ap-tap3585

I'm almost certain it's limescale as this is a problem throughout the house, so the valve needs taking apart, descaling and putting back together. I've found a YouTube video that shows me what to do so I'm going to have a crack at it myself as I can't get anyone in at the moment. The first thing I have to do is get the lever off, when it is in the open position (ie horizontal) there is a tiny little hole to the back containing a screw which you have to loosen off. Now unlike in the picture my tap is a few inches away from a wall so I can't get behind it to see what I'm doing. I've tried a number of different sized star head (torx) bits from my power screwdriver set and none of them seem to catch the screw head enough to get a purchase so that I can turn it. T10 seems to be the closest fit. The Allen keys I have don't work either. I'm wondering if the screw head is damaged or perhaps that there is some other gadget that I'm supposed to use. Any suggestions?

[kempiejon]

The Allen keys I have don't work either. I'm wondering if the screw head is damaged or perhaps that there is some other gadget that I'm supposed to use. Any suggestions?

Did you use a 2.5mm AF (across face) allen key as per instructions? https://www.howdens.com/-/media/howdens ... 75f4ed.pdf

[Fluke]

The Allen keys I have don't work either. I'm wondering if the screw head is damaged or perhaps that there is some other gadget that I'm supposed to use. Any suggestions?

Did you use a 2.5mm AF (across face) allen key as per instructions? https://www.howdens.com/-/media/howdens ... 75f4ed.pdf

Oh yeah! I didn't see those links at the bottom. Cheers Kempiejon. I have one that can't be far off but doesn't grip so I'll go in search of a 2.5mm tomorrow or Monday. Fingers crossed that sorts it.