Apologies, I wasn't trying to critisice, rather share what I'd read! Sounds like a 'let's publish positive/interesting news day'. Each outlet throwing whatever three of a hundred possibilities whilst adding the absurd link by vague geographic location only!

Although far from a sword expert, my first thought was that it didn't look British, at least not from that era. Though a lion's head is a common royal theme so a ceremonial sword sounds more likely, practical weaponry being less fancy in the whole, to my very amateur knowledge at least. Also, who's to say it wasn't thrown in at some point much later even if older than the lake.