not so young and agile now.
Never examined them closely before but the wing bolts securing the rear seat back appear to be just BSF studs peened over to secure the wingnut and a taper machined onto the other end. I suspect they are the originals.
Chalked the seal landing edge on car body and closed lid. Contact only at sides. Adjusted catch down until now a chalk line all round, three attempts. I'll wait until it rains now I think rather than get the hose pipe out.