 English Electric, as they did with many of their diesel locomotives of the 1950s-60s, did not assemble them at the Preston works, but allocated the final assembly of build numbers 2254/E7821-2273/E7840 (road no.750-769) to Robert Stephenson & Hawthorn and build numbers 2274/D353-2295/D374 (road no.770-791) to Vulcan Foundry, both English Electric plants.