The Jenny Wren is the vertical boilered version of the Lilliput. They are both similar size, in fact they share many of the same mechanical parts. The Lilliput boiler is somewhat larger, despite appearances. The length of the Lilliput boiler is equal to the height of the Jenny Wren boiler plus firebox. The engine unit is identical. It was supplied as a kit of parts, all ready machined and easily assembled with a modicum of soldering skill and a set of agile fingers being the only requirements.
The overall height is 78mm. The vertical boiler is 22mm diameter and a bit more than that in height. (Although the outer casing being integral with the firebox, it looks bigger.) It has a single flue tube, integral with the chimney. The recommended water level is "1/2 to 3/4 teaspoon" which is about 3ml. The 15mm dia. tank for the burner holds enough meths for about 10 minutes running. The meths is fed via a thin pipe to a small wick under the boiler.
The minuscule cylinder is 3mm dia. with a stroke of about 5mm. This drives the 24mm dia. flywheel at one hell of a lick with no load! There is no power take-off point provided but I'm sure the flywheel boss could be extended to provide a mounting for a pulley or gear wheel. There's not much torque but plenty of revs so, with suitable gearing, the power would not be insignificant.