The proper one in the mags was a Ford Prep'd Group A rally car.

There is a big gap between the slam panel & grill as pointed out whch makes the front look strange. Maybe used a new S2 slam panel instead of an S1 item.

don't think that you'd struggle to insure it neither as it is still an RS Turbo, but basically fitted with S1 kit instead of S2 (even tho the front ends are totally different). It is still essentially an Escort RS Turbo.
I have a friend who has turned a B plate Mk3 cabrio into a Mk4 front ended cabrio turbo. This looks strange parked next to mine tho as it looks so different.

There was also a real S1 at Lightwater Valley this yr with an S2 dash in. That looked ok as he'd used S2 full interior as well as the doorcards...unlike the ebay one:


Depends if you want an original S1 or a very good reshelled item....(thinks of Doo's old / Rob84's xr-shelled RS).