Family owners acquired the vintage car, which was in bits at the time, in 1991 when they bought the garage in Great Dunmow near Bishop’s Stortford.
The new owners set about restoring the tourer for the next 12 years, completing the project for Vauxhall’s centenary celebrations in 2003.
It’s thought that the car wasn’t used between 1934 and 1990, during which time it was dismantled and stored in the workshop by the previous garage owners.
The original owner of the car had left it at the garage after defaulting on an outstanding bill of £7 10s, around £500 in today’s money.
The model, a 30/98, was produced as a track car by Luton-based Vauxhall from 1913 to 1927.
It’s thought the name comes from its power output – 30 bhp at 1,000 rpm and 98 bhp at 3,000 rpm.
“Finished in blue and black with red leather interior, this sale represents a wonderful opportunity to acquire a most handsome example of what is considered by many knowledgeable enthusiasts to be the finest British sporting car of the vintage period.”
The auction is set to take place on June 26.