I was thinking holes in the top of seat, plastic flanges from front seats to look tidy, slide in, drill 4 holes in back of seat metal (2 either side of each prong) and jubilee clip around the prongs and seat metal through the holes........repeat for other head rest!

In fact does anyone have any headrests they want to sell, with the plastic flanges they slide through?
Any one got any pics of this done too?