Well, it's like a different car now. When I got out of it and into the Bettle this morning, I was surprised at how much better the new car felt. Having driven the Bettle for about 150 miles today, I got back in my Golf and felt very reassured that apart from the slightly firmer ride, it felt very similar to the Bettle. Tyre noise has all but gone and the feel of the steering is vastly improved.
It cost £100 + VAT, plus the two rear tyres that were worn anyway, so money well spent I reckon.