Hi Walt,
The site "BRITISH MOTOR MANUFACTURERS" - has
a page about an "Eric Longden" which says
Eric Longden was an Australian jockey who came to London to start a theatrical agency after a serious injury. He prepared and raced motorcycles at Brooklands before assembling Light Cars. The Air Navigation & Engineering Company , makers of the Bleriot-Whippet, bought his business in 1922 and built JAP and Alpha engined cars. They went into liquidation in 1927.
Does that sound like the fellow?
The Isle of Man TT site lists
the race results for an E. Longden showing results from races in 1914, 1920 and 1921.
The Isle of Man Government website also lists
race results for an "Eric Longden" which perhaps confirms that the "E" stands for "Eric".
There are some photos from the
LAT Photographic Archive shown on the Austin Harris website with the caption
"Eric Longden at 1923 JCC 200 Mile Race at Brooklands"If this is the same "Eric Longden", you may find more about him searching on "Longden Brooklands" etc.
Dave