I'm thinking of the half pedestal type basins where the full weight is hanging on these, went to one last month where they failed and the whole thing dropped to the floor ripping the tiles off. Not fitted by me!
I'm sure System3 was on about using wall anchors but don't they have to pull hard on the ceramic to tighten up?
I now much prefer wall anchors if it's into a solid wall. You have to pre-tighten them first with a socket wrench so that they expand and grip inside the wall. Here's how:
Drill a 10mm hole with a SDS drill, insert the wall anchor bolt, leaving enough threads for your basin to slip on to for fixing. Usually 50mm is more than enough.
Fit the washer and tighten the nut tight to the wall with a socket wrench or adjustable until tight. Slacken off and remove the nut and washer. The bolt is now securely fixed and expanded inside the wall.
Fit a short plastic sleeve over the threads, slip on basin over bolts, then fit a large rubber tap washer, then a steel penny washer and then the nut over the threaded bolt.
Tighten bolt until basin is secure, but never overtighten.
Absolutely solid and never moves and only costs 26p per fixing!
I use a short cutting of plastic pipe over the threads where it goes through the basin holes to protect the ceramic and a 22mm tap washer with the hole widened and a penny washer behind the nut. Very, very secure and also very cheap to buy a bag of them. A bag of ten only costs £2.59.
I've also used drop in anchors with a setting tool too with 10mm screwed rod. Fiscsher fixings are way overpriced.
Here's the ones I use:
Toolstation > Screws & Fixings > Steel Anchors > Through Bolt
