military spare wheel fixing

Hi, I have an ex mod series 3 109 with 2 spare wheels kicking around in the back, the bonnet has a spare tyre staple and rod on it and the retaining strap but I reckon that there should be something to hold the wheel onto the staple & rod on the bonnet, can anyone advise me what bits are missing or is the strap the only thing holding wheel down?

The strap does the securing and along with gravity works.
Some of the rods are drilled to allow further securing, I run a padlock through mine as an extra.
HTH,
Al

Thanks for the reply, I'll do that.