Saved Filename options

[YelloYeti]

A rather trivial question, but hopefully someone can come up with a 
solution:

my options file has the entry:
fileprefix <nameshort>-<episodeshort>-<senum>

Which when I grab an episode of a series gives me exactly what I want.

When I grab a 'one-off' programme, i.e. there is no series/episode, I 
end up with a file called name--.mp4

Is there some invocation I can use in the options file which will 
automagically get rid of the trailing '-' characters?

YY