Unless it's leaking serious quantities, and you're planning to do the Paris to Dakar rally starting tomorrow, I wouldn't panic.
It's entirely normal for a 156K mile car to dribble a bit.
If you want it looked at, I'd agree to avoid Kwik Fit. They'll probably find all sorts of other things on the car that "need" fixing, even though you replaced them last week.
On the other hand, if you know exactly what needs fixing and you've checked prices, they can be competitive. I just wouldn't trust them to diagnose anything for me, or advise me. They truly are just fitters, not engineers or mechanics.
Try to build a relationship with an independent garage where you get to speak face-to-face with the person who actually gets their hands dirty, and who will take you to the car and show you what needs doing/has been done.