These 1989 pictures of TC108/G/TD21 25938 show the much wider experimental radiator grille tried on this prototype – possibly to improve cooling? It was not seen in production. The interior view clearly shows the ‘Graber’ grouped instrument panel subsequently replaced by the triangular panel on J.J. Parkes orders.
Photos:-Nick Simpson Archive.
Alvis Archive 
This car was in our family for around 30 years and my father researched her history very thoroughly… Yes, the wider radiator was an attempt to improve cooling, done whilst the car was in the possetion of Park Ward IIRC. It didn’t work and the car would still oberheat when stuck in traffic queues etc. Apparently this problem was successfully addressed, on production cars, by fitting an electric fan instead of the regular belt-driven one.