Thomas Hill (Rotherham) started as agents for the Sentinel steam loco range, and after Sentinel were bought by Rolls-Royce, were instrumental in bringing about the Sentinel diesel loco range. In 1960 they built their own works at Kilnhurst, and created the Vanguard loco range, filling gaps that the Sentinel standard machines couldn't fulfill. After the R-R "crash" of 1971 all loco production transferred to TH(R), the works being extended in 1978. It was taken over by RFS in 1993 and subsequently work transferred to Doncaster.
Click on the link or photo below to get to the individual loco's page.