Oh, I‘m a little fanatic about the british south. We travelled Britain about 10times.
Only my wife is a little in fear: Morgan ground clearance and a farm?
Just phone ahead and let them know you will need 100mm ground clearance, any farm always has a JCB and hardcore around or scaffold planks to put down in needed areas to save the good lady any concerns.
Worth a google earth of the place, it may have a concrete track as they are important these days for disease prevention and biosecurity if they have a brain cell or two (serious farmers have many and do things professionally) - you cannot disinfect a dirt track effectively it just turns into a disease ridden mud bath.