New owner with a conundrum!

Hi I'm new to the Renault forum, and a relatively new Clio owner. I inherited the car from a good friend whose parents had the car from new, (1999) The have sadly passed away, and all the car history with them. The car, whilst quite old, only has 36,500 miles genuine! She drives really well, but has just recently developed a very annoying fault which I'm quite concerned about, any feed back welcome. After being driven for about 20 minutes or so, a rather loud noise starts up from the right front. It is definitely associated with wheel rotation. It is intermittent, which is odd, and only is audible when there is no mechanic in the vicinity! I would dearly love to get this problem fixed, but need to identify first. Any thoughts!