Thanks - I'll give Combat a go first and see how I get on!
FWIW, I had G&A after giving birth. The good thing about it is it only works as you take it, as soon as you stop breathing it in you begin stop feeling the affects of it. Granted, I then had to be 'put under' for emergency procedure and I never really thought about whether I'd fancy doing a high-energy class at the point, BUT I do remember G&A wore off very, very quickly. Hope that helps somewhat!