I believe it was you, Concordia, who mentioned Longmire, the cufflinks vendor, recently. I asked James MacAuslen about them recently, as he works close by and Jermyn Street is a small community. According to James, Longmire declared bankruptcy in order to get out of the lease of its shop on Jermyn Street. That location is now vacant (along with a few other stores in the vicinity, I am told). It seems that Longmire's intent is to move its business entirely online. Based on the evidence of the Longmire website, that is still a work in progress.
I shall miss the store on Jermyn Street. So it goes.