Many thanks for the reply, Joe - much appreciated. That's reassuring.
One other question - might be a bit of a stupid one but here goes - I've managed to find a single 9.5J, rather than an 8.5J. Until I find another 9.5, is it okay to mix different widths on the rear, i.e. one 9.5 and one 8.5, or would that cause problems?