As far as can be determined three versions of the Elf lathe were made by the Barrmor Tool Works in Easdale, near Oban, Scotland: two round-bed models (one with belt-drive and screwcutting the other plain-turning with a miniature "geared-headstock")  and a plain-turning flat-bed lathe. Whilst productions dates are uncertain some does evidence point to a span from the mid 1930s to the mid 1950s. It is known that the machines were available second-hand after World war 2 and the advertising literature, though undated, does have the appearance of that era. Unfortunately Rollo invested very little in press advertising, hence the chronology of model changes has proved almost impossible to track.
The most interesting and ingenious of the Elf trio was last to be produced, a 3.25-inch centre height by 11-inch between round-bed screwcutting model (with its bed adapted from an early 2.5-inch centre height model) that used a most unusual headstock drive system - a 3-speed Sturmey-Archer bicycle hub gear driven by a two-step pulley directly from a 960 rpm motor with an 8mm Reynold roller chain final drive. To allow for chain adjustment the Sturmey-Archer gear was carried by a pair of forked extensions to the rear of the headstock (mimicking a bicycle frame) whilst the headstock spindle ran in a pair of simple, split-adjustable, self-oiling "Oilite" bushes. The arrangement provided a useful six speeds  that, just as on a bike, could be changed without stopping and under power - the flick-lever "handlebar" control being mounted on the front face of the headstock. 
The solid, mild steel, precision-ground bed was ingeniously contrived  with a 90-degree groove machined along its length that acted, in conjunction with stiff square-section gib blocks (adjustable in two directions) to locate the carriage and tailstock. The saddle was T-slotted and carried a single 2.5-inch travel swivelling tool slide, bereft of a micrometer dial and with its gib-strip adjustment screws protruding through the top instead of side face. A 4-way toolpost, able to accept 1/4" bits, was fitted as standard. The tailstock could be set over for taper turning and its 2-inch travel spindle was fitted with a No. 1 Morse taper socket.
Threaded 8 t.p.i square the leadscrew ran through a full gun-metal nut; disengagement was by a simple dog-clutch mounted on the headstock-end bed foot and controlled by a lever topped with a moulded round finger-grip wheel in red plastic. An handwheel at the tailstock end provided a method of advancing the cutting tool under manual control.
Screwcutting changewheels were properly made from machine-cut from steel blanks and carried on an aluminium bracket. The lathe (as it seems were all Rollo's smaller machines) was finished in a glossy green oil-proof enamel with at first red (or black) knobs on all the control levers - though on the very last examples the tailstock and leadscrew handwheels were in aluminium. Little was supplied with the 70 lb Elf when new, just a 5-inch faceplate, set of changewheels, a pair of Morse centres and spanners.
Continuing the Rollo tradition of unconventional design the round-bed lathe was also available in a very much simpler form as a plain-turning version fitted with a "geared headstock", quite unlike anything seen before or since on such a small lathe. The head just a single-stage reduction and only one spindle speed. In turn the same headstock assembly was also used on a lathe with a conventional V-edged flat bed with the option of a hand-cranked drive instead of by an electric motor and V-belt pulley -  both the unusual Verschoyle and 'Damaco 5' lathes being fitted with a similar arrangement - although the height of the headstock on the Elf, and the adjustable position of the hand-crank, allowing it to be mounted anywhere on a bench instead of having to overlap the edge to let the handle be swung around. However, unlike the motor-driven version, which had the larger of the two gears gear on the spindle driven from a small gear on the pulley input shaft, the hand-cranked model (in order to obtain a reasonable top speed) had the arrangement reversed in a manner not dissimilar to that employed on old-fashioned hand-driven bench grinders.
In the absence of tumble reverse (always difficult to engineer on a very small lathe), a simple dog-clutch was fitted to the headstock-end ofthe leadscrew, engaged by a lever topped with a red knob..
If you have an Elf lathe of any type the writer would be pleased to hear from you..