Overflow on toilet dripping

I have noticed the overflow pipe keeps dripping outside, coming from my toilet. I have tried adjusting the ball lever inside the toilet, but it hasnt cured it. If i do pull it up manually though, it does stop, but i dont want to have to keep doing that. It is a pretty new toilet and ball lever.
Any ideas what the issue is?

Washer

new bathroom job if u ask me

If it's too new to be worn out, it might be swarf or grit inside. See how to turn the water supply to the WC off, then unscrew it and clean it on the kitchen table.

Slightly quicker and less work is to buy a new one for a few squid and replace it. You can still take the old one apart, see what the trouble is and fit a new washer, and keep it handy as a spare for next time.

Is the cistern fed from the water main or gravity fed from a tank in the loft? Some cistern ball valves are supplied with two different cones that fit inside and push into the washer. One has a large hole for lower pressure water and one a smaller end to the cone which will therefore exert a higher pressure on the washer to make sure it turns off with high pressure supplies.

The previous people in our house had recently had it converted from gravity to mains pressure and the plumber had not thought to check that the valves were turning off and all toilets dripped from the overflows if they were not flushed for a couple of weeks. The replacements I fitted had the alternate cone attached half way down the arm as did some of the originals when I came to change them!

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