Where can I get an accessory type head restraint for my Renault 4?

I have a 1980s Renault 4 but it has no front head restraints. Having had major neck surgery a few years ago I'm keen to have something. I'm struggling to find a pair of slide on, accessory, head restraints....

Headrest in Toyota RAV4

I test drove a Toyota RAV4 and everything was fine except the headrest. We want an upright driving position, but the angle of that headrest forces a sofa driving position. It's not good for the back, especially...