Allbon Javelin Diesels?
Allbon were an early UK company making diesels. Their first was a long stroke stovepipe of a device of 3-port configuration and 2.8 cc capacity (0.18 cu in).
In 1949 the Arden style of shaft valve porting and radial transfer ports hit the UK in a big way via a motor made in Liverpool - the Elfin 1.8 cc (0.11 cu in). It revolutionised diesel design in this country and in a matter of months everyone was jumping on the banwagon. One of those doing the jumping was Allbon who in early 1950 produced a glow 1.5 cc (09) called the Arrow which wasn't teribnly well received - few over here had even heard of nitro at the time and few were familiar with glow operation so the Arrow was very quickly folowed by the Javelin - same size and weight and a good bit more powerful. Later that year a scaled down version, the Dart, of 0.5 cc (0.03 cu in) was introduced. Both, but especially the Dart, were very successful - the Javelin had strong oppositiopn from a new Elfin of identical size, whereas the Dart had its own market niche.
If your motors say Allbon on the side they are early ones - the first darts had green anodised heads, Javelins were always red. Later darts also had red heads. Around 1956 (don't quote me on that) the company was taken over by Davies-Charlton and subsequent version had 'DC' on the side of the crankcase rather than Allbon. Can't remember when production stopped - around 1960s IIRC
Hope this helps - I still have an early Javelin but stupidly parted with a couple of early darts years back - wish I'd kept them just to gloat over!
Mike