Down there in Camden Market there selling garanteed female producing seeds. What are these like? Do they yield female plants. Also how do they manage that? It was my understanding that plants can change sex anytime.

erm - its rather hit and miss! to be frank, if you're lucky, you may get all ladies, but far more likely you'll get some hermies too, who'll pollenate your ladies just as effectively!
Also, take into account you are going to put four or more months of love, care, hassle and risk of a grow into that crop - start with shite seeds, you'll end up with no crop, or a crap crop! You can get good fertile beans from the uk420 shop for under £20 - we know they work, are from reputable suppliers, and are properly kept - on some things there are bargains to be had in the market, but not seeds!
ps for a newbie, howsabout the flying dutchman's "the pure" at £18.95 - good hardy plants, lovely buzz, not too long to flower..................

good to see another londoner on the board as vlad said the pure is very good allround and from a reputable breeder and is alot cheaper then some of the other stuff out there

Have used DP feminized seeds many,many, many times and only ever had 1 hermie early on. Sometimes right towards end of flowering plants may start to show signs of male flowers but that's right at the end, as, I would have thought ,many plants would do in an attempt to spread their genes.........
BushBandicoot