Welcome to the mad world of the Austin 7.
As you are new to the car, here's some background that I hope you'll find useful - there is, of course, even more if you search online:

CLUBS:
There are so many Austin 7 clubs that, in 1969, an association of them was formed - and this is now the go-to place that hosts a mass of important data: https://a7ca.org/
It's a large site with lists of clubs, a superb archive of historical data, reproduction handbooks, chassis and car registers, A7 history, A7 model identification, events, etc, - explore the A7CA website at: https://a7ca.org

The page that links to the most important sections is: https://archive.a7ca.org/

DIRECT LINKS to HANDBOOKS, PARTS MANUALS, and SALES CATALOGUES
A comprehensive collection can be downloaded as PDFs: https://archive.a7ca.org/collections/han...rts-lists/

Sales brochures can be found here: https://archive.a7ca.org/collections/show-brochures/

The Pre-War A7 club has a useful Facebook page:
https://www.facebook.com/groups/pwa7c .... with other enthusiasts forming Facebook groups for their club, or for specific models or regional interests.
As a club member, you will receive not only the club's magazine, but also the Association Magazine, published quarterly since 1970 https://a7ca.org/about-us/magazine/

BACKGROUND HISTORY and BOOKS:
To read the fascinating background to the car - with reproductions of the notebook by Stanley Edge, the car's design draftsman see: https://a7ca.org/austin-seven/the-people/

Austin 7 books can be bought from: http://www.pwa7c.co.uk/bookshop.php There is a good collection of material, including historical and technical literature with data on specific models such as the Type 65 and Nippy, Grasshopper and Ulster, etc.
For engine, other mechanical work and restorations one highly recommended business with personal attention, vast experience of the Seven and much helpful advice is: http://www.albaaustins.co.uk

IS YOUR CAR ALREADY LISTED?
The A7CA provides a list of known Austin 7s - now over 12,500 - at https://a7ca.org/chassis-register/ check to see if your car is listed (or add it, that would be very useful). It includes versions by English Austin, American Austin and Bantam, German Dixi and BMW, and French Rosengart. You can search the database by Model Type, and chassis, car, and registration numbers.
For the 100th anniversary of the Seven's introduction in 2022, a thousand cars attended a special Centenary event: watch the film here: https://a7centenary.com/

Chassis Numbers:
Most Sevens before the Ruby, a car introduced in 1934,  had the chassis number stamped on the nearside chassis rail just behind the rear engine bolt. This was accompanied by two narrow, aluminium plates riveted to the nearside bulkhead; one was stamped with the Chassis Number, the other the Car Number.
In the UK, many Sevens were registered when new using the Car Number, not the Chassis Number (the Austin Motor Co. always asked for the Car Number, not the chassis number).
Stamped into the transmission tunnel just behind the handbrake (the rectangular cover plate for the latter might need removing to find it) is the 'Model Type,', e.g. AF, AE, RN, etc.
By 1936, most Sevens used a Car Number incorporating the chassis number; e.g. for the Nippy, the plate had the Car Number prefix AEB plus the body number - the latter stamped into the top of the transmission tunnel just aft of the handbrake.

For complete restorations and all types of specialist Austin 7 mechanical work try:
Ruairidh Dunford dunford1@aol.com Phone: 0141-942-8037

For new Austin 7 parts try these links - in no particular order of recommendation:

David Cochraine at: https://www.a7c.co.uk/aboutus.php

Jamie Rogerson at: https://www.theaustinsevenworkshop.com/

http://austinrepro.com/ This company offers standard and also beautifully made, difficult-to-find reproductions of headlamps, speedometers, rev counters and various items for standard cars and also the Swallow, Nippy, Ulster, etc:

For both new, used and some refurbished parts try:
Tony Betts at http://www.7ca.co.uk he has a wonderful range of new crankshafts, conrods, pistons, blocks and chassis parts etc.
Other suppliers of new and used parts include:
Southern Sevens: http://www.southernsevens.co.uk
Ian Tillman  http://www.oxfordshiresevens.co.uk/welcome-to-oxfordshire-sevens/

A helpful link (though some parts are out of date) with details of other repairers, restorers, gearbox, suspension and bodywork experts, etc: https://oldcarservices.co.uk/austin-seven-specialists/ (some of these will be out of data)

The Cornwall Austin 7 Club's website is especially useful with lists of suppliers and much really helpful technical advice, etc. https://www.austin7.org/

If you want to know about 'Technical Data & Specifications', of the Austin 7 this page will help: https://www.austin7.org/DataPages

For detailed information about the Austin 65 and Nippy Sports models see:
https://aus7in.wordpress.com/

For detailed information about the Ulster Sports models see: https://ulster7.wordpress.com/

For detailed information about Gordon England versions see: https://gordonenglandregister.wordpress.com/

INTERESTING ODDS and ENDS

For 25+ pages of digitally restored, attractive and high-resolution Austin illustrations (some of which you can click on and download) see http://www.lathes.co.uk/austin7

Fitting indicators, a guide is available here: http://www.lathes.co.uk/austin-7-indicators

Improving the lights: http://www.lathes.co.uk/austin7-2/page18.html