Well, it turns out I did one of the things without even knowing it!! Kensington Roof Gardens is on the 6th floor of 99 Derry Street and dates back from the 1930s. Its now been turned into a restuarant and nightclub which is a bit of a shame but I have to say the food way great and on the flip side I am pretty sure you wouldnt be able to see the gardens unless they have the restaurant.
Note to those interested in going...book in advance and save your pennies!
This isnt my picture, its from here