Bottle washers.

[Chippy_Tea]

10 Homebrew Beer Cider Screw On Bottle Cap Washers Approx - 25mm Outside Diameter & 15mm diameter hole.

https://www.ebay.co.uk/itm/284134221468?mkevt=1&mkcid=28&chn=ps

 

[flamingo]

Thanks for that Chippy.
They look likely to be a good very cheap alternative to keep as a reserve.
Thanks again.

 

[reddibaggie]

10 Homebrew Beer Cider Screw On Bottle Cap Washers Approx - 25mm Outside Diameter & 15mm diameter hole.

https://www.ebay.co.uk/itm/284134221468?mkevt=1&mkcid=28&chn=ps

https://brewingathome.co.uk/product/bakelite-stone-replacement-rubber-washers-x-10/There you go hope these are what you are after

 

[flamingo]

Hi Chippy,
These are also very good, I’m having some. With what you’ve turned up to date I should never have this problem again.
Many thanks.

 

[Chippy_Tea]

Glad i could help.