From its design "The Sundale", with its screw-on Selig Sonnenthal badge - would appear to have been made in the period 1880 to 1900. Some significant features, common on small to medium sized lathes of that time, included an outboard-mounted thrust bearing for the spindle; a narrow bed with an especially deep, detachable bridge section; crank handwheels on the carriage, cross slide and top-slide feeds (and a lack of micrometer dials); inverted V-ways on the cross slide; a bed-mounted rack of very coarse pitch, bolt-on hangers for each end of the leadscrew and a tailstock with the barrel section having fresh air beneath it. However, this particular example, with a double flywheel, full-length foot treadle with chain connectors (instead of flat-bar drive cranks) and machine-cut backgears, of better-than-average quality.
The use of the logo "The Sundale" in inverted commas was a common way of disguising - while at the same time admitting -  that this was a machine made not by the "Sundale Company, but by a manufacturer who, having supplied one of its larger agents or dealers had been persuaded to remain anonymous. With some resistance in the UK at the time to continental imports, there is a very good chance that the maker was German..