Hi Azz .. sorry but cannot help with a boot lock retainer, .. just fitted mine ( had to lock the Missus in the boot, as she has smaller hands, to get it fitted) and am now fitting front door locks and have noticed that the small round lock that the key goes into looks like it has the same retaining clip that the boot lock has, if someone on the Forum can confirm this, then it may be easier to get a door lock retaining clip from a donor car or station wagon
? .. hope this helps .. Regards Stephen