It although I've never had an issue with a farm tractor.
.
I have! Last night. Actually, last night's ride was not fun.
Tractor on narrow lane, heading my way, lights on full. Me with hand over my eyes to have a fighting chance of seeing anything. Mud
swamp on the road meaning both hands would have been much better off on the handlebars

Then two WVM, again on a narrow lane. One who just about let me scrape past. The other coming up the other way, who apparently took exception at having to reverse to make way for the other WVM shot past me at crazy speed, two wheels up the verge, mud flying everywhere. Oh and some nob'ead in a car (no idea what sort) again had me pressed up against a bloody hedge so he could get past. And he was laughing as he went past

.
I was seriously considering purchasing an airhorn thingy to frighten the living wotsit out of anyone else who does this on the next ride.