As a long term lobbyist against smacking children, spanking, slapping, etc etc whether a "little tap" or anything, I know there are lots of anti-smackers on Mumsnet too.
If you do share that view then respond to this consultation
www.homeoffice.gov.uk/publications/about-us/consultations/definition-domestic-violence/dv-definition-consultation?view=Binary
on that issue - where it talks about violence against those under 18 there is no reason at all why the bill (which in some aspects I do not accept which is why I happened to be looking at it) should not be a great vehicle to get all smacking banned, not just smacking which leaves a mark which is the current ridiculous English law and is a typical British fudge.
You can respond direct to the consultation and/or ask your MP to take a particular stance on it.
On the other proposals in the consultation I would be against legal changes as there is too much scope for abuse of the proposed new law.