Hi, I am sorting through some Unipart boxed shock absorbers and have found one stamped Land Rover BMK258. I’m struggling to find a reference to it.

All the other three are marked GSA71185 which comes up Leyland Sherpa. The Land Rover one has the same open and closed length and similar resistance from hand compression, to the Sherpa ones.

Can someone say what sort of Landie BMK258 is from please?