Toilet cistern side entry inlet valve problem

[ResGate]

Hi - I'm a baffled DIY plumber! I wish to renew my side-entry toilet cistern inlet valve as it's noisy and filling up slowly. The inlet valve plastic pipe (PS they say brass ones are better when it comes to renewing) which comes out of the cistern is 3/4 inch (I unscrewed and measured it) which then attaches to the cold water flexible hose input. I literally trawled all the internet - or so it seemed - to find a new inlet valve to fit but they all seem to be either 1/2 or 3/8 inch. I could not find any 3/4 inch. The inlet valve is old (well over 15 years) so is it obsolete or am I being thick and missing something glaringly obvious? Any advice appreciated. Thank you

 

[snowhead]

Your valve is 1/2", you've measure the outside of the thread, the size is the hole through the inside.

3/4" and many other sizes large exist, but are only used on commercial water systems.