We used Alla last month ( see my review for NCL Sun) and had excellent treatment. We couldn't fault them in any way. Jacquie.
Why not try Alla and Red Oktober - they all have excellent reviews. Denrus hve the contract to provide the tours for P & O so they may decline to take you on (though I have heard that this no longer applies) .
We have just come back from the Baltic on P&O Oriana and did the 2 day value tour with Denrus. There were no problems booking and the 2 days were excellent - only 7 of us on the minibus with a superb guide. We saw much more than the majority of P&O passengers and could not fault Denrus in the slightest. Highly recommended from all aspects, booking, communication, tour, lunches everything. Hope this helps.
Thanks for your reply. My wife and I have now booked the Denrus 2 day excursion. A couple of further questions please. From reading the Denrus documentation it would appear that US dollars are acceptable in Russia, is this the case or did you need to obtain Roubles? Is tipping allowed for the guides and, if so, do they prefer dollars or roubles?