Spring onions flowering...

I was just going to pull up the last few spring onions ( white Lisbon) from last year and use them up as ordinary onions, when I noticed that a couple are flowering.  As I was about to go and get some new seed I wondered if I could just wait a couple of weeks for the seed to set and then plant it straight away instead?  Last year I just chucked them in the soil and whilst I'm sure they didn't all grow, there were certainly plenty, so they obviously like my plot. 

Not sure where you've seen that, but White Lisbon is not an F1.

You would not get an F1 and a non-F1 with the same name.

I think they've made a mistake on the web page. It also says it flowers well in the sun!

It doesn't say F1 on the packet.

So will it take long for the flower to set the seed?  and then will it be ok to sow straight away, or will it not grow until next year (sorry if this is a stupid question, as I don't know the answer I have to ask!).