"MichaelJP" wrote in message
.. .
snip

Could anyone tell me what it means when the met plot an occluded front as
in
the one just SW of Cornwall on the chart above, but it has no line
associated with it, just the symbols?


In this case it indicates the feature in undergoing frontolysis.

See http://homepage.ntlworld.com/booty.weather/FAQ/AF.htm

Jon.