Farmers IHT Planning

Tiger

Ok this is a bit specialist but I thought i'd ask the question??
Situation Farmer 400+ acres buildings equipment etc etc.
Wants to retire and gift the land and buildings 50/50 to his sons, retain ownership of and continue to live in the farmhouse.
The farmhouse and garden would likely not be in an acceptable proportion to the farmers retained farming activities and would therefore be unlikely
to qualify for agric property relief. The house would then presumably be fully chargable to IHT or CGT?? Can he claim Principal private residence relief instead?? Can this be claimed by the estate after death??

There are other options, contract or share farming that would solve this problem but the family are reluctant due to other personal reasons!!!

Can anyone add any other suggestions??
Thanks
Tiger (roar!!)