At £10000 per acre this translates to

Clarkson
1,000 acres
1.56 square miles
£10,000,000 value

Lloyd Webber
4,000 acres
6.25 square miles
£40,000,000 value

Viscount Rothermere
4,700 acres
7.34 square miles
£47,000,000 value

Dyson farm
36,000 acres
56.25 square miles
£360,000,000 value