no toilet humour here

[Squibbly]

everytime i get the plumber there always seems to be a leak where the inlet goes, this is a new modern toilet instead of coming through the top, like the old ball and chain, it keeps letting out water, ok when the plumber originally fitted it, it wouldnt stop the supply coming in and it took along time to fill up, and there was leaking water to the kitchen below. any ideas, should i get a professional plumber i.e. corgi? or is that gas? the plumber my bruv got turns out he is a builder from down the street

[DIY]

I can't understand what you are on about. Is the leak from a soldered copper joint, a copper compression fitting or a plastic threaded joint? That will determine how to fix the leak.

[Squibbly]

looks like a plastic threaded joint

[DIY]

In that case I would use clear silicone sanitary sealant. You may be able to find some in a small tube (similar to a tube of toothpaste) otherwise you will need to buy a cartridge of the stuff and use a cartridge gun. If the fitting is under water you will need to shut off the water supply then drain the cistern, then undo the leaking fitting, dry it off, smear sealant on the flange, washer, plastic nut or thread (depending on the site of the leak) re-assemble, tighten up, leave for 20 minutes while the sealant goes off, then it should be water tight.