Not a bad little project if she has a solid shell, bit of paint work, get the lump running could look a nice little motor for someone working to a budget.
I would take some shots of the engine bay, interior, tyre tread, and generally more close up shots in and around the car.
Peeps will be more inclined to start thinking about it if they can see all round it.
£550 aint to bad really, take into consideration the trim, alloys (if good tyres), S1 kit, bootlid and spoiler and your up close to the money right there.