Oh dear, I'm running out of pictures. (At last! I hear some of you cry.)
Here's a couple of people we haven't seen before: Les Gough taking the high line against a competitor on the Melbourne Motordrome in December 1924, and R. Lyall who was riding at Newcastle, north of Sydney, in May 1926. Not much detail one the bikes I'm afraid.
I have a number of other photos, but most are very poor quality and add nothing to our RA story. One thing that is clear is that after the 1924 season RAs in Australia took on a look very similar to the catalogue description: in particular the goose neck frame was the dominant design and the sloping top tube frame was seen only rarely. Perhaps the Douglas factory realised there was no particular advantage, or need, for the sloping frame, and that the home product would stand up fine in Australian conditions.
One thing I haven't mentioned is the other Douglas models used for racing in Australia in the 1924-1928 period.
In Douglas lore the RA was superseded by the TT (both referred to as the "Isle of Man Model" in the period) for 1926, but although there are a few period photos of TT Models in Australia, it's clear that the RA remained the chosen machine for dirt track/speedway use. The use of TT Models in the dirt was very rare. Similarly OBs did take to the track, but if period photos are anything to go by they were about as uncommon as TTs. The large number of surviving OBs (or OB/RA, OB/DT composites) that have survived in Australia more-or-less as they were last raced are probably products of impecunious amateur racers from the 1930s and 40s - the number of OB racers in major events in the 1920s was very small.
I have some more comments that I will add in time, but while I'm getting my thoughts together I'd love to see Australian photos of RA/RW/TW bikes that anyone else can contribute to the thread.
Have a great Christmas.
Leon