There's a bit of mixing up UK 'intellectual property' law here.
A patent applies to an 'invention', not a 'part'. It must be "new or novel", it must have a use and it cannot be something that is obvious. A patent must be applied for prior to marketing. To be patented, a part would need to be something which is the first of its kind, a unique way of achieving something. Quite a high bar. Difficult to see it being applied to typical Lucas accessories, unless whatever it does had never before been possible in this way, e.g. it was the first ever solid state rectifier.
It is possible to gain some rights to a design if it is not a novel piece of technology, but it is unique in some less technical way, for example, its appearance. 'Design Rights' can be protected under separate rules as a registered or unregistered design. The protection is less absolute than a patent, but is easier to secure, a more practical test.
A drawing or piece of writing can be protected by 'copyright.'
The name 'Lucas' can be protected as a registered 'Trade Mark' with the (R) Mark. If a company owns a trade mark, it must continue to use it, or it can be struck off the register. Use can include licensing the trade mark to another company / multiple companies. Typically, trade mark licence agreements contain controls on the quality of what is produced by the licencee.
This is also true of patent and other intellectual property ("IP") rights owners. The manufacturing rights can be licensed. Hence product can be made and quality controlled by a number of businesses other than the owner of the trade mark, design rights, copyright or patent. But the quality criteria should be those set by the IP owner in the Licence Agreement.
Don't know if that helps, just needed to get it off my chest!
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