Noise from tyre

Evening fellow Panda fans
I wondered if anyone had experienced a similar problem to mine - I have noticed over the past month the front driver's tyre has been making a 'swooshing' noise as it rotates. Sounds like a plastic bag is stuch to the tread surface, a funny squelching sound on each rotation of the tyre. As you go along at 40 you can hear it when you lower the car window, like a slap,slap,slap sound. I think it might be something to do with the tyre tread.
Possibly harmless but annoying. Hope it doesn't start to disintrigrate!
I might be replacing the original Continentals soon after 15,000 miles on the front anyhow perhaps for Michelins or a better make as I find the grip in the wet very poor.
PS - Has anyone fitted the vented front disc brakes from the Sporting, wonder if they are a straight swap?

i would check the tyre over closely,perhaps a damaged sidewall flexing at speed?
brakes would most likely bolt on but you would need dics and calipers plus it depends on the wheel design if theres clearence for the calipers