Thanks for all the responses about the Tillston Hellenic.
I managed to get in touch with Bill Tillston, the son of the original builder, William, who now runs a motorbike dealers in Stockton on Tees.
Bill very generously sent me an envelope full of different coloured sets of down tube transfers, some of which I'll send to Nick Tithecott at Lloyds so copies will be available in future.
Not that there will be much demand - Bill said that his father built about 150 frames before moving into the motorbike business in the 1960's. He said he mainly used to make them for friends - so presumably it was a very local business.
I suppose it shows how strong the 'high-end' lightweight market was in the 1950's that there were such small scale builders who nonetheless aspired to make 'special' bikes.
Wyndham Pulman-Jones
Girton, Cambs., UK.