Mike
Thank you for your continued info. Apparently I do not have access to a "complete" archive of Kelly's Directories. I have 1900 and 1905 from ancestry.com... nothing in between. Is there an online source for these?
I agree with the concept that the listing in 1903 indicates the business was there in 1902. I just don't have a complete set to probe (have 1895, 1897, 1899, [1900 is available], 1905, 1908, and 1915). The "Webb's Lane" location is news to me because of the incomplete nature of the directories on ancestry.com.
The patents held by XL'ALL (and a number of others unrelated to motorcycles) were all registered to Timothy Shepherd who died at age 75 in 1937. In most patent applications he gave his residential address, but on some of them he gave these various addresses of business. By 1914, he apparently took up residence at "The Woodlands" on Wake Green Road in Moseley and apparently remained in that vicinity until he died. I don't know how it's done in the UK, but in the USA, there would ordinarily be a probate record, even in the case of a will, of the disposition of assets following death. Such a record might give a hint as to the state of the company when he died, but since it has not been 100 years since he died, those records may not be available.
With respect to the maps, I am stumbling through the interface at
https://maps.nls.uk/ to try and find things, but I cannot always tell the date of the map they present. So if you have a handier reference that makes it easier to find locations, that would be great.
Mark