A contractor has provided us with a prototype product which is very good quality. It is an offline, non-isolated , SMPS LED driver of 10W. It has no metal shielding and is in a plastic enclosure. It passes conducted EMC, but has some radiated EMC failures at peaks between 60MHz to 250MHz. We don’t wish to use an expensive cable ferrite in the mains cable, but rather, wish to use a low inductance common mode choke right next to the mains input connector, on the PCB itself…..this will simply be three turns of enamelled wire (ie three for live and three for neutral) round a small ring ferrite torroid. (part number = ZC41206TC by mag-inc.com)

(There is already a high inductance (1.1mH) common mode choke, further downstream, in the AC filter)

The product is supplied by only live and neutral wires..no earth wire.

Ferrite torroid datasheet

We believe that this will have sufficiently low interwinding capacitance such that it will not be easy for high frequency emissions to get past it.
We wonder why such things are not commonly available off the shelf?