Hi Peter,
I am really glad you posted this, and the great thing is that the 'learning curve' applies to us all, and we get to learn together. As noted, I have not ever seen this name nor this particular type of panel on blades of this period, and it was reassuring that Richard had not either. He has outstanding expertise on regulation military swords, and the author of many impressive articles on them, so if he concurs I feel confident that we are on the same page.
I think this is likely contemporary with the M1796 issues or slightly after and using this 'guarantee' was intended to align with Gill's lead in the climate of the time. These were the first 'official' issue swords and during considerable competition for contracts, and from what I understand the regimental commanders puchased them from the Board of Ordnance, who had in turn received them in bulk orders from contractors.
What puzzles me is that these are essentially blank blades, as it does not seem that Tomlinson was a maker. Blanks would have come from Germany as if made in England they would have had a makers name on the back of the blade as was the practice. This panel is basically a 'marketing panel' and with a company name rather than makers, and certainly it would have been in poor form to place the 'guarantee' of Gill's ilk on a German blade. Yet this does seem of the period and I think the observations on the wear are quite viable, especially coming from professional context.
The use of this 'warranted' phraseology seems to have waned after the first decade of the 19th century, and it is not known on British blades after this pattern (as far as I know).
The British M1796 was a somewhat widely exported sword, and the blades were in use even more as these sabres were surplussed and entered many colonial regions. The blade form itself was even produced for Indian colonial use in the latter 19th century. What eliminates the plausibility of these later circumstances is the period that the 'warranted' phrase puts the context of this panel in, which is c.1800-1810.
Photos of the entire sabre will help, and further review is needed regarding the other examples known with this panel and name. Most firm names in these times were engraved in cursive script it seems and in cartouche on the scabbard throats of usually officers swords. Troopers swords of course were bulk purchase and not afforded this attention.
It truly is a fascinating example and good discussion, so I really look forward to further developments.
BTW, thank you for the note on the Villasur site!!! You know that got my attention !!!
All the very best,
JIm