Well the noise has stopped!
On Monday a couple of guys from my work came home with me at lunch time to see if we could work out where the noise was coming from. After driving up and down my drive about 10 times, we reckoned it was coming from the front near-side wheel.
That afternoon, I phoned Kwik-Fit to get a free brake check
as I figured it *could* be something to do with the brakes, and it would be handy because they would have it up on a ramp anyway.
So I took it down to them the next day. One of the guys there took it for a test drive with me, and we could clearly hear the sound. Then I left them for 1h as they put it on the ramp. So everything to do with the brakes was fine. Turned out oneof the other guys then took it out for a test drive but he could not hear any sound.
I went under the car with them having a look at everything. Eventually we noticed that it looked like the CV joint had been scraping against something in part of its rotation. In fact the contact was clearly with the end of a bolt which is directly below the CV joint. Whilst up on the ramp there was a clear gap of at least 20-30mm between this bolt and the CV joint and apparently there is no way they should come in to contact. I guess you'd have to have been under the car to know the bolt I'm talking about.
Anyway, when I then drove the car away, I could not hear the sound any more. It has just gone!
So it does seem that that bolt was touching the CV joint - fortunately it doesn't look like it's caused any damage.
So what could have caused this? Well... I have a theory!
Where I park my car there is a very shallow kerb. Normally I park flush to it (the drive is quite narrow and other cars go past), sometimes I park with two wheel up, and occasionally when my parking is not spot on, I might leave a tyre a little bit wedged against the kerb (my bad!). So the car had been sat outside my house for 2 weeks, but well parked. However, I think that maybe for the first few days I had it parked with the front nearside wheel touching the kerb (I can't remember to be honest - I'm pretty sure I moved it after a few days when a space closer to my flat was available). I wonder if this parking could have temporarily moved the wheel, and somehow it was relieved by being up on the ramp and jacked up?
Does this sound plausible?
(Kwik-Fit free brake check much recommended - they guys were on my car for over an hour with no charge. Brilliant!)