Message in a bottle

Nice walk on the beach and no1 son found a message in a bottle!
He found it above the high tide mark on the beach at Pleinmont.
The note says it was cast in the sea in 1998.
The note enclosed was written in French and English language and asked the finder to make contact.
Bizarre thing is, it was from a person in Guernsey so, quite where it spent the intervening 16 years is a mystery.
Did it float up and down the bay of St Malo or, has it lain unfound on the beach all this time or, was it trapped and released by the recent stormy weather!
Who knows!
8-)