I can understand anyones fear of booking a tour other than the ships tours when confronted with mixed and conflicting advise over visas.
Let me make it quite clear .. if you are considering a tour of St Petersburg and visiting on a cruise as we did then you have nothing to worry about.
When I made the booking I expected to pay in advance, but that is not required at all. You simply confirm that you want to book, you print off the tickets which also act as your visa and then pay on Day two of the trip.
We had Marina who was excellent in her explanations, descriptions and her exceptional command of the english language.
If I had one gripe it was the visit to the souvenir shop. where we paid for the tour. Totally not what we wanted, but I know probably essential for the limited shopping time available.
Apart from this, we used an ear piece with receivers so that we could move freely around and listen t the same time.
We visited everything and more.
Listening to those back on the ship about the ships tour we knew we made the right dcision when we heard the groups were two and three times the size, stopped too often and too long for toilet breaks.
All in all excellent and highly recommended.