Hi - if you have a small leak on the front of the radiator, it may be an indicator of more serious issues with your system - such as the type of water in your area causing corrosion, may be rust in the system causing blockages etc. Best to get a plumber to look at it - particularly if the bottoms of all of your radiators are cool in the middle/bottom, not the top (which would be air in them, and needing bleeding).
Cool at the bottom, while hot at the top means sediment of some sort has built up.
I had an issue with a leak in a pipe under the concrete floor, 2 "bubbles" on rads, and rust on another when I bought our house. I knew there was an issue with the whole system and factored it into the cost of buying. Had to ulimately replace all 14 rads, the boiler, burner and header tank...
The moral of this is, any doubt, get it checked out NOW, not when it starts springing expensive holes around the house.