Oil leak

[wrightzer009]

Seems to have a very small oil leak, 

I noticed the other morning after a night rain there was oil on the ground, but thought maybe it was coming from the another car on the street as the car was parked on the road, 

When the rain dried up i parked her for about 4 hours on a dry patch but there was nothing so i thought it must be someones else car, 

But the next morning when i came out i can see small pact on ground about half the size of a mobile phone on the driver side, 

its 3 days now since i first noticed & the oil hasn't changed on the dipstick so must only be happing very slowly when parked & i can not see anything when i look into the engine from above, There is a guard on the bottom i don't have the tolls to take it off 

 

Any idea where it could be form before i take it to the garage. 

 

I have a 530 k round trip  drive i have to make the weekend, would it be safe to do it