Recommend a good pub near the Marble arch in London?

Answer 1

Jemima, depending on what type of establishment you like there are quite a number near Marble Arch.

For a more traditional English Pub try The Carpenters Arms (even sounds very English):
http://www.beerintheevening.com/pubs/s/49/4937/Carpenters_Arms/Marble_Arch
Or The Quebec:
http://www.beerintheevening.com/pubs/s/26/261/Quebec/Marble_Arch

If you prefer an upmarket modern bar, then you will enjoy The Tyburn:
http://www.beerintheevening.com/pubs/s/75/7549/Tyburn/Marble_Arch

These links all have streetfront photographs, addresses, map and features (such as food available) and user reviews.
The reviews can be helpful when selecting a place.

This is just three, but this site has others.