Originally Posted by Colonel Mustard

Just posting closure here.

I ended up booking a tour from Hanoi at a fairly reasonable price. The tour was great apart from the rude and pushy tour guide (Poseidon run by Halong Marguerite i believe).

I think i would have preferred to make my own way down to Cat Ba island and arrange the tour from here though although the quality of the tour was guaranteed by my Hanoi hotel (Royal Hotel. Recommended!).