A little summary for future reference.
Day 1: arrive at Pulkovo airport at 1.40pm and promptly run into trouble with immigration
Day 2 - walked for a good 4 - 5 hours before succumbing to the heat and getting on a hop on hop off bus. Great bus tour! 600 rubles. Really interesting commentary, nice slow ride so I could take in everything from the comfort of a bus. Free dinner at the hostel - Russian pancakes with condensed milk. Odd but delicious.
Day 3 - 1.5 hr boat tour with anglotourismo, 1000roubles. Tour itself was ok but it was an open top boat and doing it at 12noon on a hot sunny day probably was not the best idea... Took the sapSan train to moscow, fabulous ride. Comfy and spacious, polite staff who spoke English, got a hot drink, bottled water, a sandwich and a biscuit included.
Day 4.. Walking tour at 10.30am, went with a girl I met at the hostel. Unfortunately had to be cut short because she fainted in the heat... Oh well there is still tomorrow and I was probably close to fainting as well. Had two (TWO!!) scoops of icecream. Pistachio and mango. What a holiday so far.