Intermittent Wheel Squeak

[bezzawezza]

My Peugeot 407 2.0 HDI has, for a few months, developed a strange squeaking noise from one of the drivers side wheels. Unable to exactly tell if front or back if I'm honest. It's not a constant whine more like a rythmic squeak as the wheel turns.
It only happens when going straight I think, if I turn slightly or apply the brakes then it stops temporarily to appear again a short while later (not immediately). I had it checked by a garage when it first started a few months back who were unable to replicate it sadly. Since then I have had the wheels off (once for a puncture on the front, and the rear for a tyre change). On the occasion when the front was off the noise went away for a while but returned after a week or so.
I have concerns that it may be a wheel bearing but there is no rumbling, vibration or anything like that just this intermittent squeak. If it does turn out to be the bearing what would a ball park figure for repair be?