I am too struggling to loose those annoying pounds that just wont come off. I've tried many classes but I found that most don't target the Post Natal areas or don't have the expertise.
For expert advise and training I go to
ProPhysio in Earlsfield (just behind Barclays Bank)
020 8879 1555
They do Post Natal Classes on Tue & Thurs at 2.30 and you can bring your baby (which is great - though until they start crawling).
They also offer Pilates on Tues & Wed nights as well as Sat mornning at 9.
I started off doing just the post natal class once a week with Gemma but am now doing Pilates as many times a week as I possibly can b/c Michelle the pilates instructor is unbeliavable - and the work out you get in those targeted areas is fantastic. The cost of classes is very reasonable, and I've been going since my baby was 10 weeks - I've now lost over a stone and feel great, though still have a way to go.