John Lewis Arc Tap O Ring Kit 1425R , if your Tap is dripping where the Spout meets the Base.  Here is our Guide: How to change a Kitchen Tap O Ring Kit Guide.

If your Tap is dripping from the Spout then you might need to replace the John Lewis Arc Tap Valves.

Here is the link to all our John Lewis Arc Kitchen Tap Parts.
Note on the Grub screw included with the O Ring Kit: The grub screw takes a 2.5mm allen key. Please retain your existing grub screw in case it is an earlier version in which case you will need to use your existing grub screw.  This O Ring Kit covers several different UK Kitchen Taps so you might not require all the O Rings provided in the Kit.