Changes to Agricultural or Forestry Tractors and Tractor Components (Type Approval) 1988
S.I. 1988/1567
Made by Agricultural or Forestry Tractors and Tractor Components (Type Approval) 1989
3 changes. All changes to Agricultural or Forestry Tractors and Tractor Components (Type Approval) 1988
From legislation.gov.uk's record of changes, the official one: see it there.