Thanks for the advice and the offers, reassuring to know it's not serious, since there are no problems with running I think I'll see how it goes.
I did get the feeling that Nissan (Widnes) were trying to drum up business, in the same breath I was advised to get 2 rear tyres (at £500), the aircon belt (due to age cracks), the rear brakes done (which are OK), to think about rear disks (also OK), etc... I know the dealerships are having a hard time but this is driving business away.
Much appreciated.