Re the Allport lock. William Allport was the son of William Ketland's partner, James Allport. James Allport took over management of the company when WK died in 1803. This was specified in his will as was the stipulation that he pay WK's wife an annual stipend of £150. James Allport fell sick quite soon after and effective control of the company was in the hands of his son, William. When James died in 1816 the partnership automatically dissolved and William found himself out of a job because WK's widow turned control over to her brother, William Izon. It's quite clear that WK did not trust his brother-in-law and, as things eventually turned out, was right in that.
William Allport set up in business under his own name, hence the locks we often see marked "Allport late with Ketland & Co.". So...no W. Allport lock can pre-date 1816. Of course, these were all made in the B'ham trade, Neither the Allports or the Ketlands made locks. As an aside, the Allports had been neighbors of the Ketlands in Aldridge, the village outside Birmingham they came from and it is very likely that they had all known each other since childhood.