Sense resistor in switching node

[Faringdon]

Hi,
Today we wanted to measure the secondary current in the forward converter 240vac, 150w, 37vout.
The thing is, due to it being the switching node (as attached), even though we twisted the flying probe to the sense resistor, it stops working, then starts again as soon as we remove the flying probe.

Do you agree this is the switching node creating noise?....and when we solder the flying probe to the sense resistor,  the flying probe acts liek a noisy antenna which stops the forward from working.
We can  remove wndings from a common mode choke. and wind 100 turns on it and use that as a sense transformer, but were hoping not to bother with that.

As you can see, because the rectifier is capacitive coupled to the sec coil, both sides of the secondary are switching nodes....so looks like we are stuffed.