Basket Hilted Broadsword Regimental Question

I acquired this broadsword from my Dad, along with some other bits and bobs, which he had collected some years ago.

It is, I believe, an early 19th Century pattern Highland regimental Broadsword, obviously parade-ware only though it obviously has seen a fair bit of active wear, with the metal scabbard particularly showing signs of use.

Going by the Battle Honours (all of which look to be from the Peninsula Campaign but before South Africa, I think the sword is from the Argyll & Sutherland Highlanders, and with the motto, "Ne Obliviscaris" ('Do Not Forget, the motto of Clan Campbell) and the Boar's Head, also Clan Campbell, this seems to borne out.

However, on the reverse, there is the motto "Fortes Fortuna Juvat" (Fortune favours the Bold), also with a Boars head, which perhaps indicates the owner being a MacKinnon (though this motto is used by many families and indeed regiments about the world) and again this doesn't go with the crest of a mailed arm with sword.

I'm really looking for some of you Nineteenth Century buffs out there, with a bit more knowledge of the period than me,  to confirm the likely regimental origin of the blade and it's likely service date.