Jensen's factory floor ledger books are held at The Herbert Museum in Coventry. They were moved there over 10 years ago from the Coventry Museum of Motor Transport (it has the Rootes cars, and The Herbert has some Rootes papers).
The Rootes Archive Centre Trust in Banbury, England in conjunction with the British Sunbeam Tiger Club has a faithful copy, now also in a digital format.
The Herbert letter is styled "Certificate of Vehicle Authenticity' and this has at times been abused in Tiger sales particulars. The Herbert museum operates on a shoe string, is slow to change and sadly cannot afford scruples.
In my view the Rootes Archive Centre Trust provides a more informative certificate, and by making checks avoids onward misuse. Fees received by the RACT directly support the preservation of Rootes Motors heritage. As a retired Trustee, I would of course recommend Tiger owners make the RACT their first choice for a heritage certificate.
Regarding 'Rootes Assembly Orders' to Jensen Motors. Each individual order was numbered - hence the 'ROTA'# in the factory ledger. They were connected to a specific partially trimmed and painted body shell upon their arrival from Pressed Steel co.
On being hauled onto the Jensen assembly track the ROTA order was placed behind the windscreen and the ROTA number chalked on the windscreen. In an exampled case of MK1A - B382002110 LRX the ROTA docket was dated 8th May 1966 and it has a Jensen Date of 18th May 1966. It hasn't been possible to find out what day the machine entered the track. Since fettling was often necessary, the Jensen date was most probably the final day day before despatch to Ryton, Coventry for pre-delivery inspection etc.
There are no known records of Rootes build orders to Pressed Steel Co, so it isn't possible to accurately date when they were put together at Cowley. What can be noted is the Jensen date range of each JAL series.
This is merely a 'broad brush' guide.
