Antenatal classes in England, NHS vs Private?

Anyone else in the UK who are considering their antenatal classes now?

I don’t know whether to just stick with the two classes offered for free on the NHS and one of their breastfeeding workshops or to pay privately for a longer 6 session group class?

Has anyone done either of these? Or combined some with their own research such as a book or dvd?

Is two sessions really going to be enough if I want to be really informed?

The private classes I’m looking at are with the NCT.

Thanks for any opinions!