Art Unwin wrote:
"Actually, I see nothing wrong with such an assembly and in fact have
seen a military configuration such as this where two such antennas were
used in a V shaped form where the narrow ends were placed together and
enclosing an approx 30 degree angle."

Such an antenna may be called a pyramidal log-periodic.

A version is included in Kraus on page 398. Its boom-separation angle is
60 degrees.

A pyramidal log periodic is the cover story in the July 1969 "Popular
Electronics". This is a construction article beginning on page 27. The
author is George Monser. It uses 17 rods on each boom, every rod
different from the others on a boom. Separation angle for the booms is
also 60 degrees. This antenna covers VHF and UHF TV and FM broadcast
bands. It is said to match 300-ohm feedline over the range and produce
enough gain for "deep-fringe" color reception.

The longest element (not aligned end-to-end as a dipole) is 115-in. tip
to tip, or 1/2-wave at about 51 MHz.

Best regards, Richard Harrison, KB5WZI

Many thanks to all who contributed to this thread, I visited the Lab
again today and realised that they have corrected the mistake!

I don't know if it's because of my insistence, or that they just
couldn't get it to work properly, but to see a result is pleasing!

More power to your (collective) elbow!