Ok. I forgot to put the "PM only" bit, and having been off-line a couple of days you seem to have it all wrapped up between you.

Katlaughing got 18 of the answers, and in full. (Sorry Sorcha, even where there is a clear connection it's nice to have answers which answer the questions, such as St Petersburg for #2 rather than just 'Peter')
And the two Kat missed were indeed:
11 St George's Channel
12 St Leger.

Number 13 gives rise to the old joke about the two skiers trapped by an avalanche, who spot an approaching St Bernard dog with the tradition small keg of brandy around its neck.
"Look, here's man's best friend"
"Yes, and there's a dog carrying it!"

CHEERS

Nigel