Creffield Blackstock
Precision engineers, maker of truck and tractor components
1960 Spark Holdings acquired T. R. Creffield and Son[1]
1962 Spark Holdings acquired Blackstock Engineering Co of Enfield, doubling the precision engineering interests[2]
1965 Spark moved its factory from Enfield[3]
By 1973 the 2 companies were associated as Creffield/Blackstock, precision engineers, part of Heenan Spark[4]
1975 Acquired by Weyburn Engineering Co[5]