Whoooooo.....finally a uk webiste that sells gyneflex-

http://www.myhealthcentre.com/products.asp?category=Wom...category=Accessories

I am 21, never had childen, and in terms of weight I can carry about 400g with my vagina. Shall I just get the 'firm' one? It says they come in packs of tow, so I suppose it would contain 5 & 6?

Yes. Buy the firm, because even if you are at a lower level you will want to graduate to the highest level.

If you find you can't flex it at all, then you will need to get the pink set too.