Plug stuck in sink

[Longshanks]

Morning

Had a new sink fitted about a year ago with one of those spring plugs that are supposed to pop up when you apply pressure.

It got stuck yesterday but I managed to remove it and then decided to unscrew the whole thing and give it a good clean etc. I then screwed it back in and now it stuck fast and seems to be deeper then before.

I may have somehow overtightened it but is there a way of loosening. I've tried to press down, get small screwdriver underneath but nothing works.

Many thanks

L

 

[Longshanks]

Thanks for your help.

Have now removed it with a screwdriver and scratched the top of the plug in the process.