I read that the Seat Leon Estate is more firmly sprung than the Golf, which otherwise appears to be identical.

There are 2 suspension types on the platform used by both the Golf and Leon. When we bought our Leon only Leons with more than 150 PS got the fully independant set up whereas Golfs with more than 120 PS got the fully independant set up.

Our Leon is 140 PS thus has the simple rear axle and I can tell you that after 2 years daily use its fine. That said its the SE version, the FR with lowered sports suspension may be a different story.

Is this true - to draw younger buyers perhaps?

Seat has always tried to attract the younger buyer so nothing new there.

Are there any other material differences?

Plenty. The first is the price, our Leon cost £5000 less than a Golf with the same engine and very similar spec.

Visit dealers, try both, compare specs and prices and do what I did, make your own mind up. its you that has to drive it.