Yes there is an Austrian connection, its the designer of the Micronair rotary atomiser Edward Julius Bals who was born in Austria, he moved to England in the 1930's then China, Asia and Ski Lanka before returning to England. http://pubs.rsc.org/en/content/articlelanding/2000/po/b006350i#!divAbstract http://www.fwi.co.uk/machinery/best-of-british-micron-sprayers.htm
The earliest Turbair with an O&R engine is the Turbair 21, the leaflet isn't dated but given the fact the engine is described as being under 1HP it will date from around the mid 1960's (the 1HP engine became available in 1965). The price then was £45 for the sprayer & £8 extra for a wheel fitting, the address given is Edward Bals (Sprayers) Ltd of Turbair Works, Bromyard, Herefordshire. Thanks to Paul (pmackellow) for the pictures from the leaflet.
I have also found a patent from Edwards Bals of Turbair Works, Bromyard that was applied for in June 1964 for a sprayer that looks similar to the Turbair 21; https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=GB&NR=1105652A&KC=A&FT=D&ND=3&date=19680313&DB=&locale=en_EP#
I suspect that this crop sprayer maybe a Turbair 21, it appeared on an Italian small ads website a few years ago.
There is also an earlier engine powered sprayer patented by Edward Bals (applied for in 1961) this was made by Birfield Engineering/Micron Sprayers and known as the Micronette 26 & 75; https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=3221993A&KC=A&FT=D&ND=3&date=19651207&DB=&locale=en_EP#
The later O&R powered Turbair was sold by Edward Bals (Sprayers) Ltd of Bromyard, Herefordshire as the Turbair Tot and by Turbair Ltd (PBI) of Britannica Works, Waltham Abbey, Essex as the Turbair Tot 2S, PBI also made a lot of the chemicals for crop spraying & pesticides for killing flies, some of the chemicals available then are still in use today, but banned chemicals vary for different countries. It's worth finding out the PPE requirements for using these chemicals, they can also be harmful/fatal to animals & pets as well as us.
The O&R engines made after June 1967 are easy to date using the engine serial number code, the engines on mine date from 1968 I also have the engine dating from 1974 that was from a Turbair.
The Turbair TOT eventually became the Turbair Fox (powered by the Italian Fox Engine) when O&R/AEP engines were discontinued, the last 2 stroke version offered by Micron was the Turbair Motafan (still using the Fox engine), the newest one I've seen dates from 1998.
Only the electric versions are still made by the Micron Group, they were re-branded in Jan 2013 from the Turbair Electrafan to the Micron Electrafan; http://www.microngroup.com/micron_group_has_rebranded
The battery powered Micron Electrafan is currently being sold for £365, which doesn't included a battery pack (another £100).
http://www.daltonengineering.co.uk/consumables/fly-spray-prevent-auto/electrafan-sprayer-12v-excl-battery-pack.html
David