1. It's probably done 15-20k miles, mostly motorway in my ownership and would have had new oil 8k miles ago.
2. It's whining really quite loudly now and has been getting progressively worse. At first I thought I was imagining it, now I know it's definitely far too loud.
3. Interestingly the whining seems linked to engine load as well as RPM. Tried left foot braking while accelerating and it definitely gets louder. I'm still trying to get my head around how this is possibly because engine load isn't transmitted through the belt to the charger. My only conclusion was that opening the throttle plate was "letting the noise out" as you can hear the noise coming from the air filter.
I'll check oil level ASAP but sadly my thinking is that if it's too low now, the damage has been done.
Are they difficult to remove / refit? I'm wondering about doing it myself to save pennies and just boxing it up to send it to Lynx.