Maybe this is a stupid question but wouldn't it be possible to just shield the original toroids from electromagnetic influences?
I have a small copper cube made from plumbers Sheet copper in mind which could be connected to the ground on the underside. Or is this just a little bit na?ve?
I would actually give it a try myself - but as I do not have a spectrum analyzer, I would not be able to find out if it did help or not.
Of course changing them to SMD inductors is easier - but this way the high Q toroids could be preserved.