Harrison M450 Lathe - early version, often badged "17-inch" in the USA and some other markets and with headstock control levers tipped with tapered black knobs. The end cover over the changewheels has a distinctive, large circle cast in at the top. 
Large, and detailedInstruction Manual, Maintenance Manual and a Parts Manual as useful Exploded Assembly Diagrams with 10 electrical schematics covering the various versions. This lathe has been found with two different screwcutting gearboxes, one of which is probably a changeover model. Both sets of screwcutting charts are included. This edition shows both headstock clutch/brake types. Details of this lathe on my site here: https://www.lathes.co.uk/harrison-m/page5.html
For the late version of this lathe, which had black facia panels on headstock and screwcutting gearbox, see MHL450L