ISTR that the Jodderell Bank techs would track down leaky microwaves and ask the owners politely could they do something with them. Can't recall where I got that from though.
Top Interesting Facts About Jodrell Bank Observatory
A very short article about interference at Jodrell Bank (old page with out of date links)
The SKA | Jodrell Bank Centre for Astrophysics
ETA - just found this from 2016. This demonstrates the conflict of probable increased interference vs pressures for housing. When JB was built the site was chosen for it's relative freedom from interference.
Jodrell Bank: Inquiry considers whether new houses would affect telescope