I'm looking for a saw that will happily cut 6mm thick fused glass - the information above says it cuts 3mm art glass ?

You can use the Mega Blade on the Taurus Ringsaw to cut up to 6 mm glass https://warm-glass.co.uk/taurus-3-mega-blade-kit-p-2823.html

If you are cutting glass in straight lines the Trim Saw can cut glass up to 20 mm thickness https://warm-glass.co.uk/diamond-trim-saw-with-diamond-wheel-p-3575.html