That is helpful Buckbrush.
Enfield is the name of the Royal Small Arms Factory at Enfield Lock in London. They were a government owned and run factory that did not sell to the public. There was another govt factory at Sparkbrook in Birmingham.
BSA (Birmngham Small Arms) and LSA (London Small Arms) were privately owned factories that would manufacture Lee Enfield rifles under contract to the government. There was a strong demand for private sales to fill the need of militia and volunteer units that were formed and organised at that time with private funding. The govt allowed them to manufacture for the public under licence, as it was in the interests of the Empire that sales were allowed. It was considered a good thing that citizens were involved in shooting sports and some Lee Speeds were top of the line target rifles.
Any rifle that was made for the commercial market would be required to display patent information. The patent for the action was held by James Paris Lee and the patent for the box magazine and other features were held by Joseph Speed, a senior manager at RSAF Enfield. Hence a commercial version of the Lee Enfield would have Lee-Speed patents marked on the action.
Patents at that time had to be registered to an individual, not a business entity, so Speed being the top banana introducing these features, prepared and registered the patent on behalf of the Govt. LSA also made commercial varients of the service rifle, so they too manufactured what became known as Lee-Speed rifles.
The patent expired in 1914 (I think) and no longer needed to be marked on the product.
Both BSA and LSA made full specification military arms and also made sporting rifles, all marked Lee-Speed, but in recent times, the term is now used to describe a short stocked sporting arm, even if not marked with the patents.
Cordite was a brutal propellant , the main ingredient being nitro glycerine. It had a sharp pressure spike and burnt very hot. Modern commercial ammo uses a much milder propellant with a lower pressure spike and lighter bullets, and is loaded to ensure that it will be safe to use in any good condition rifle that will chamber it (litigation concerns).
So have at her with off the shelf ammo. Stay clear of old army surplus stuff as sometimes the primer can be corrosive and will rust your barrel in short time if not cleaned properly after use.