The rates pre 1992 were higher 50 to 60%, yet farms stayed in the family (in some cases)
50 or 60% tax, with no 10yr pay back period or exemptions, is still a great deal of money to find, irrespective of land values, which even now have not gone up in proportion to housing.
The farm i worked on, became unviable, 100 acres owned, 100 acres rented and the land sold to a pension company in the late 80s, the land is still extensively farmed, incorporated into larger and ever larger farms.
The loss of subsidy, which many farmers voted for, is a huge issue for farmers, as is the buying power of the supermarket.