According to "Air Britain's Airlines of the British Isles since 1919" Alidair was formed as a subsidiary of the Alida Packaging Group on 1st January 1972. If this were the case then ownership must have moved on by the time of the Flight article in 1973. The Alida Packaging Group did have a Beagle Pup based at Hucknall which would make appearances at East Midlands, so there was possibly a link somewhere.
I don't believe Alidair had anything to do with Kestrel, who ceased trading on 1st November 1972 and whose sole Viscount (G-AVJB) was returned to BMA.
Thanks for the replies, helps me with a large project which I have been working on for a couple of years.