The Marina Park, Lagos website has a page here with distances and a map:
http://www.marinapark.net/eng/localization.htm
Be aware the times quoted are based on having a car.
The is a fairly steep hill up from the Marina Roundabout to the Marina Park.
Most Restaurants and bars should be still open in tehh first week of September.
Weather Underground showing a long range forecast for cooler weather for Lagos next week:
http://www.wunderground.com/cgi-bin/findweather/getForecast?query=Lagos,%20Portugal&wuSelect=WEATHER
Average Mean max. daytime temp. for Lagos for 1st week of September is 24 °C. (Source: Weather Underground.)
