missorinoco I just go at my own speed on round 2 of L2 6W6P. I use a 4kg weight and I'd much rather focus on the quality and form of my movements than trying to whizz through them. I do find it a good workout for my core, and remember- if you can build up good thigh muscles they will help burn a lot of calories as they are such big muscles.
Jackster and Stunt- how are you measuring body fat? I've used the US Navy calculator and that comes up at about 23% (I'm just a shade under 5ft6 and 9st3, so pretty similar to you two). However, my Tanita scales vary between about 25% and 27%. I think from being measured before with callipers etc that the scales overstated by about 10%, so that would tally up. There are very few truly accurate ways to measure so it's best guess really I think!
Heavy weights, low reps is the best way to gain muscle, plus plenty of protein for repair. So 3 sets of about 5-8 reps is recommended. I've been using the dumbbells for things like chest press and shoulder press to try and improve my upper body strength, plus for weighted squats.
I'dkick- were you just doing the kettlebell dvds or did you try classes too? I've now done 2 beginner classes with our local kettlebell club and I can see how terrible SIWW is for form etc. The club I've started at really focus on form, and most of the moves are fairly high weight/low reps to try and build muscle with swings and higher rep moves for cardio/conditioning. Her turkish get ups for instance are much too fast and she comes up in a crunch rather than hinging like you should. I think the kettlebells she sells are rather light (20lb max, so 9kg, and they aren't using them with all the weights in), so I think most people would be ok doing those moves with a light weight but the poor form would be a killer with heavier weights. I haven't seen any BH kettlebells so I couldn't comment on form for that.