Original Stratos at Classics at the Castle.

[strat24v]

ditto

I'd say more likely it being to fit mud and snow super tough type tyres.

[ChrisCar6]

I think Safari and snow rallies cars used stradale-type rear arches.

[ProtoTipo]

I think Safari and snow rallies cars used stradale-type rear arches.

Yes, but note that the tub has group 4 wheel arch flairs fitted.
So that the Stradale and wide arched rear panels can be swapped.